Effects of change in smoking habits on bladder cancer incidence in Tunisia

doi:10.4236/health.2011.310103

Paper Menu >>

Journal Menu >>

Vol.3, No.10, 613-619 (2011)

doi:10.4236/health.2011.310103

Health

Effects of change in smoking habits on bladder cancer

incidence in Tunisia

Dhafer Mrizak1, Fatma B'chir1,2, Mehdi Jaida ne3, Maurice Jean Arnaud4, Saâd Sa guem1*

1Metabolic Biophysics and Applied Pharmacology Laboratory, Department of Biophysics, Medicine Faculty of Sousse, Sousse,

Tunisia; *Corresponding Author: [email protected]

2Laboratory of Natural Substances, National Institute of Research and Physical Chemical Analysis, Technopole Sidi Thabet, Tunisia;

3Urolology Department of Central Hospital University (CHU), Sahloul-Sousse, T un isia;

4Nutrition & Biochemistry, Bourg Dessous 2A, La Tour de Peilz, Switzerland.

Received 22 January 2011; revised 19 February 2011; accepted 28, February 2011.

ABSTRACT

Bladder cancer is among the most frequently

diagnosed cancer. Tobacco smoking exposures

involving nitrosamines and aromatic amines

are the main cause of bladder cancer. Although

cigarette consumption has gradually decreased,

an increased incidence of bladder cancer was

registered among males Tunisian for the last tw o

decades. A similar increased incidence of lung

adenocarcinoma and bladder cancer was regis-

tered among Tunisian males. Epidemiological

results suggest that changes in cigarette smok-

ing may be the cause of the increased inciden-

ce of bladder cancer. The relationship between

CYP1A2 enzyme activities, a key enzyme for

activation of bladder carcinogens, and bladder

cancer risk was investigated. Variations in CYP1

A2 activities measured in patients with bladder

cancer and healthy smokers showed a signify-

cantly higher CYP1A2 metabolic activity in

patient group. Changing in cigarette smoking

habits associated to the variation in CYP1A2

activity seem to explain pa rtly the increase inci-

dence of bladder cancer observed in Tunisian

male population.

Keywords: Cigarette Filter; Smoking;

Bladder Canc er ; CYP1A2 Activity

1. INTRODUCTION

Bladder cancer is the most frequent urogenital cancer

in Tunisia and rank at the second position in the world

[1], among male populations.

Epidemiologic and biological studies have clearly es-

tablished that cigarette smoking is the main cause of

bladder cancer [2,3] and it was suggested that more than

60% of all bladder cancer cases may be attributed to

tobacco smoking [4,5].

Although stabilization and even decrease frequencies

of major cancers types which are associated to smoking

such as lung cancer and oral cavity cancer, a dramatic

increase in the incidence of bladder cancer was regis-

tered in Tunisian Cancer Centers for the last two decades.

This increasing prevalence has been also reported

worldwide [6,7] and may be the result of changes in

smoking behavior in particular when the cigarette with

filter had replaced those with no filter.

The concentrations of specific carcinogens such as toba-

cco-specific nitrosamines (TSNs) and Aromatic Amines

(AA) have been increased in filtered cigarette smoke [8].

It has been suggested that the consumption of those

cigarettes with filters may contribute to increase bladder

exposure to tobacco carcinogens thus leading to a higher

risk of cancer devel opment [8-10].

The aim of this study was to evaluate from epidemi-

ological and biological data whether the introduction of

cigarette with filter could explain the remarkable in-

crease of bladder cancer incidence observed in Tunisian

population.

2. MATERIALS & METHODS

2.1. Epidemiological Study

Data of epidemiological study were obtained from

CHU Central Tunisian hospital registers (Department of

Anatomy Pathology of CHU Farhat Hached of Sousse,

Tunisia) for the 1987-2005 time period and the evolu-

tion of bladder cancer incidence in Tunisian males was

evaluated.

2.2. Biological Study

This study was carried out at the Faculty of Medicine

of Sousse by the Biophysics laboratory where the as-

sessment of CYP1A2 enzyme activity was measured by

F. B'chir et al. / Health 3 (2011) 613-619

614

caffeine test among bladder cancer and healthy smoker ’s

subjects.

CYP1A2 activity was estimated in vivo using caffeine

as a probe drug and reversed–phase HPLC method was

developed to measure plasma caffeine and paraxanthine

concentrations to determine the CYP1A2 activity from

the ratio paraxanthine/caffeine.

2.3. Subjects

14 patients with bladder cancer and 14 healthy subje-

cts were recruited for this study.

All subjects are current smokers. They gave their info-

rmed consent and the study protocol was approved by

the local Ethical Committee.

All subject abstained to drink any beverages contain-

ing caffeine for more than 24 hours before and during

the study.

2.4. Methods

The subjects were asked to fill a questionnaire where the

total consumption of coffee and other caffeine-containing

beverages as well as the number daily cigarettes smoked

and the period of smoking were recorded (Table 1).

The subjects were coming at the hospital in the morn-

ing at 8 am and ingested 140 mg of caffeine disso lved in

150 ml warm water. A single 5 ml blood sample was co-

llected directly in EDTA tube four hours after caffeine

ingestion.

Blood samples were immediately centrifuged at 3000

rpm for 15 minutes and plasma samples collected were

stored at –20˚C until analyzed.

2.5. HPLC Plasma Analysis and Caffeine

Concentrations

To 0.5 ml defrost plasma was added 300 mg of ammo-

nium sulfate and after 1 minute vigorous shaking (Vor-

tex), 3 ml of ethyl acetate and isopropyl alcohol (8/2, v/v)

were added. After shaking for 2 minutes, the samples

were centrifuged at 4000 rpm for 25 minutes and 2.5 ml

of the organic phases were collected, dried at 56˚C under

a flow of nitrogen gas and the residue obtained was dis-

solved in 100 µl KH2PO4 buffer solution.

Table 1. Averages daily cigarettes smoked and smoking period

in bladder cancer patients and healthy controls.

Groups Bladder cancer

patients Healthy control

Daily cigarettes smoked 25 20

Smoking period (years) 43.5* 26.78

*P < 0.05

HPLC (Agilent 1200) separation was performed using

two reversed phase columns in series (Hypersil ODS 4 ×

250 mm, 5 µm) and (Eclipse XD B-C18 4.6 × 150 mm, 5

µm) maintained at 33˚C with a direct injection of 5 µl of

the extract. An U.V diode array was used for the analytic

detection. Elution was performed by gradient mode us-

ing two mobiles phases A and B. Phase A solution was

composed of water, tetrahydrofurane (THF), acetic acid

and acetonitrile (986/3/1/10 v/v respectively). The phase

B solution was acetonitrile. The gradient program was

chosen as follows: B was set at 0% for the 20 first min-

utes, increased linearly to 4% at 35minutes, reached to

8% from 45 to 50 minutes and return to 0% at 55 min-

utes.

Plasma caffeine and the concentrations of its metabo-

lites were calculated by CHEMSTATION software using

calibrations curves already estab lished.

2.6. Measurement of Caffeine Metabolic

Ratio

Caffeine is mainly metabolized by the hepatic CYP1A2

enzyme and is currently used as a probe for the measure-

ment of CYP1A2 activity. In the metabolism of caffeine,

the first demethylation steps gave paraxanthine (PX, 17X),

theobromine (TB, 37X) and theophylline (TP, 13X).

About 80% of the met abolism of caffeine is going through

the paraxanthine pathway mediated by CYP1A2 [11].

The measurement of the concentration ratio PX to

caffeine (PX/CA) was used as a metabolic marker to

evaluate the CYP1A2 activity.

2.7. Statistical Analysis

Mann–Whitney U test was used to examine differen-

ces in distributions of smoking period and caffeine meta-

bolic ratio between cases and controls.

3. RESULTS

3.1. Epidemiological Study

3.1.1. Ev olution of the Incidence o f Tobacco

Related Cancers in Tunisia

This study recorded the most frequent cancer associ-

ated to tobacco use in the Tunisian male population: lar-

ynx, oral cavity, bladder and lung.

The frequencies of these four cancers obtained from

CHU Cancer register of Sousse are calculated for two

periods 1987-1990 (PI) and 2002-2005 (PII). In Figure

1 is shown the evolution of the incidence curves of lung,

bladder, oral cavity and larynx cancers for the time pe-

riod 1987-2005.

Although stabilization and even a small declin e in the

F. B'chir et al. / Health 3 (2011) 613-619

615615

Figure 1. Incidence evolution of four tobacco-related cancers

in Tunisia between the time periods PI (1987-1990) and PII

(2002-2005).

incidence was observed for lung, larynx and oral cavity

cancers, an increase of the incidence of bladder cancer

was observed for the 2002-2005 period when compared

to the 1987-1990 period. Bladder cancer frequencies

exhibited increase from 7.69% in 1990 to 13.03% in

2005 and thus doub le in 15 years.

3.1.2. Evolution of Lung Cancer and Its

Histological Forms Incidence in Tunisian

Population

According to our previous study [12], the distribution

of lung cancer incidence compared to its major histo-

logical types the adenocarcinoma (AD) and the squam-

ous cell carcinoma (SCC) was not similar for the last

two decades in Tu nisi an p op u lat i on.

As shown in Figure 2 a slow decline in the incidence

for both total lung cancer and SCC was observed from

1990 up to 2005 per iod, while a con tinuous incr ease was

registered for AD incidence.

3.1.3. Comparative Analysis of the Bladder

Cancer and AD Frequenci e s Evolution

In Figure 3 is shown the evolution of the incid ence of

AD and bladder cancer for the 1987-2005 period. The

evolution of both frequencies of bladder cancer and AD

were similar during the same period of time. Bladder

cancer and AD have gradually and simultaneous in-

creased for these last two decades in Tunisian males.

3.2. Biological Study

3.2.1. Separation of Caffeine and Its Metabolites

The Figure 4 illustrates the chromatographic profiles

of caffeine and its metabolites measured at 280nm in

plasmatic sample of one patient and one healthy subject.

The chromatogram shows a complete separation of caf-

feine and its metabolites, in particular for TP, TB and PX.

This good separation allows an accurate quantification

of caffeine metabolites concentrations and consequently

Figure 2. Incidence evolution of AD, SCC and lung cancer in

Tunisia between the time periods PI (1987-1990) and PII

(2002-2005).

Figure 3. Evolution profile of AD and bladder cancer for the

1987-2005 period.

37X: 3,7 dimethylxanthine (theobromine); 17X: 1,7-dimethylxanthine

(paraxanthine); 13X: 1,3-diméthylxanthine (theophylline), SI: Inter-

nal Standard; CA: 1,3,7-trimethylxanthine (caffeine).

Figure 4. Chromatograms of plasma samples of caffeine and

its metabolites among one patient (blue) and one control sub-

ject (red).

the determination of the PX/CA metabolic ratios. The

chromatographic profiles of plasma show that there was

no interference with endogenous compounds.

3.2.2. CYP1A2 Activity Evaluation

Variations in PX/CA ratio were observed in Figure 5

between patients and healthy subjects. These variations

suggest wide interindividual differences in CYP1A2 ac-

tivities. The average PX/CA ratio was 0.42 for the bladder

F. B'chir et al. / Health 3 (2011) 613-619

616

Patients

Controlgroup

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

Plasmatic ratio PX/CA

Figure 5. Distribution of PX/CA plasmatic ratio values among

patients and control group.

cancer group and 0.3 for healthy group of subjects. The

CYP1A2 activity was thus significant higher in the

bladder cancer patient group compared to healthy group

(P < 0.05).

4. DISCUSSION

In the present study, biological and epidemiological

investigations show that the rapid increase in the inci-

dence of bladder cancer observed for the last two dec-

ades in Tunisian population may be related to the change

in smoking behavior when the cigarettes with filter had

substituted progressively those with no filter.

More than 50 years ago, tobacco use was suggested as

a major etiologic risk factor for bladder cancer [8,13]

and 60% was attributed to cigarette smoking [4]. Many

case-control studies reported that smokers have at least a

two-fold higher risk of developing bladder cancer com-

pared to non smokers [8,14]. Bladder cancer is estimated

as the second cancer localization attributed to smoking

after the lung [15].

The epidemiological results of this study show an op-

posite evolution of bladder and total lung cancer fre-

quencies for the time period 1987-2005. Despite the sta-

bility of lung cancer incidence in Tunisian males for the

1987-2005 period (Figure 3), a two-fold increased

bladder cancer frequency was registered from 7.69% in

1990 to 13.06% in 2005. This dramatic increase of

bladder cancer incidence registered in Tunisia was also

reported all over the world during the same time period.

Cancer registers show a larger increase in Denmark, in

USA and in France among men and a somewhat smaller

increase among women [16,17]. This incidence is still

increasing overtime. It has been suggested that heavy

cigarette smoking plays a major role in increasing blad-

der cancer incidence [18]. This conclusion was also con-

firmed in our work. Patients with bladder cancer are

heavier smokers that subjects in the control group (Table

1).

How can be explained the apparent disagreement be-

tween the increase incidence of bladder cancer and the

decline of the lung cancer frequency with a change in

smoking behavior. We suggested that the changes in

smoking behavior associated to the increased use of ciga-

rettes with filter may explain the changes observed [12].

In this study was reported a stabilization of the total inci-

dence of lung cancer while a continuous and significant

increase of AD over SCC forms was observed among

Tunisian population for the tim e-period 1987-2005.

Figure 6 shows that the 10.5% incidence of SCC is

unchanged while that of AD exhibits an increase from

3.1% in 1990 to 7.2% in 2005. Th is increase of AD was

related to the introduction of cigarette with filter [12].

This new smoking habit appeared to be more carcino-

genic through the increasing incidence of AD, the most

aggressive and metastasis cell types of lung carcinoma

[19]. The smoker of cigarette with filter is more exposed

to tobacco nitrosamines (TSNs) in particular the 4-me-

thylnitrosamino-1-3-pyridyl-1-butanone (NNK); a potent

carcinogen which induce lung tumors in the peripheral

lung regions, the areas where the AD occurs [12,20].

The significant increase of bladder cancer observed

during the 1987-2005 time-period parallels the evolu-

tion of AD incidence in Tunisian population suggesting

that both pathologies may have the same origin. The

most prominent change in smoking habit reported during

this period was the increased use of cigarettes with filter.

Filter cigarette deliver at least 60% less nicotine and tar

than plain cigarette [5,8].While this change leads to a

lower exposure of polycyclic aromatic hydrocarbons

(PAHs), the concentrations of aromatic amine increased

by 59% from 1968 to 1985 [8] and between 1978 and

1995, the concentrations of tobacco-specific nitrosmines

in filtered cigarettes increased 17% for N’-nitrosonorni-

cotine and 44% for 4-(methylnitrosamino)-1-(3-pyridyl)-

1-butanone [8,21]. Some N-nitroso-compounds such N NK

have been suggested to be involved as causative agents

in human lung carcinogenesis leading to the AD type

[20,22].

Figure 6. Trends of the evolution of AD and SCC in Tunisia.

F. B'chir et al. / Health 3 (2011) 613-619

617617

Moreover, the smoker’s dependence on nicotine may

lead to smoking more cigarettes with filter because they

contain lower amounts of nicotine. To achieve the de-

sired physiological response to nicotine, smokers of low-

tar filter cigarettes tend to adapt their smoking patterns

by taking larger puffs, increasing puff frequency and

inhaling more deeply. Such changing smoking patterns

showed that although the smoker-weighted carbon mo-

noxide-yield of ventilated filter cigarettes was 21% less

than that of plain cigarettes, blood carboxyhemoglobin

level in ventilated filter cigarettes was 7% higher than

those found in men who smoked plain cigarettes [23].

These data are consistent with the conclusion that smok-

ers who are addicted to low-nicotine cigarettes may take

more intense smoking and deeper inhalation of the smo-

ke leading to a higher amount of carcinogenic tar parti-

cles, in the bronchi and bladder of the smoker [24].

Although the increasing incidences of AD and bladder

cancer may have the same origin with the use of ciga-

rette filter, they have different carcinogenic inducers.

PAHs such as benzo(a) pyrene (BaP) and TSNs like

NNK are the most known tobacco smoke potent car-

cinogens as shown on animal model [25,26]. PAHs and

NNK cause mainly lung cancers, PAHs induce the SCC

tumours occurring in bronchi and bronchioles of the

lungs and NNK induce AD predominately in the deeper

region of the lung. In animals exposed to the mainstream

cigarettes smoke develop bladder cancer while animals

treated with BaP or NNK develop cancers on other loca-

lizations than the bladder [27]. Thus, the induction of

bladder tumours by tobacco substances inhaled is not

dependent upon PAHs and TSNs, but may dependent on

other tobacco chemicals [18,28]. It was reported that

aromatic amines are potent bladder carcinogens [29].

Bladder tumours induced in animals with tobacco aro-

matic amines carcinogens [30] showed that these com-

pounds do not elicit directly bladder tumours but the

effects were due to some of their metabolites. Among

these tobacco amines carcinogens, 2-naphthylamine and

4-aminobiphenyl were found to be the most potent

bladder carcinogens in man [31]. The most direct-acting

carcinogens that are reactive electrophilic agents are

produced through in vivo activation involving an initial

oxidation catalyzed primarily by hepatic cytochromes

P450 [31], the first critical step in this bio activatio n [32,

33]. 2-Naphthylamine and the 4-aminobiphenyl are me-

tabolized mainly in liver to N-hydroxy-4-naphthylamine

(N-OH-naphthylamine) and N-OH-aminobiphenyl re-

spectively. These reactive metabolites produce human

epithelium DNA adducts in liver and bladder. The enzy-

me primarily responsible for the N-hydroxylation of 2-

naphthylamine and the 4-aminobiphenyl, the initial step

for carcinogenic process, is the CYP1A2 [31]. This key

enzyme in the activation of bladder cancer carcinogens

exhibits wide variations in activity explaining individual

susceptibility to chemical carcinogenesis and thus to

bladder cancer development.

In smokers, the results of this study show a significant

higher CYP1A2 activity in patients with bladder cancer

when compared with healthy subjects. High CYP1A2

activity is therefore suggested as a susceptibility factor

of bladder cancer. The polymorphic CYP1A2 activity

may be related to environment and genetic factors. Ex-

posure to tobacco smoke is known as a potent inducer of

CYP1A2 activity [34,35] but there are other occupa-

tional and dietary inducers. Variation in CYP1A2 activ-

ity was also related to polymorphisms in the CYP1A2

genes and consequently the effect of cigarette filter on

the risk of bladder cancer development is dependent on

this polymorphism. Further investigations on the role of

CYP1A2 polymorphisms on the risk of bladder cancer

performed on larger population of smokers are needed.

5. CONCLUSIONS

This epidemiological study suggests that the increased

incidence of bladder cancer may be attributed t o change i n

smoking habit associated to the substitution of plain ciga-

rette to cigarette with filter while the effect of smoking

duration cannot be excluded. As bladder carcinogens,

such as aromatic amines, are mainly metabolised by

CYP1A2 enzyme, a signif icantly higher CYP1A2 activity

observed in bladder cancers patients when compared to

control subjects suggests that high CYP1A2 activity

could be a susceptible factor for bladder cancer in sm-

okers. Changing in cigarette smoking habit associated to

higher enzyme activity may be considered as a potential

biomarker in the aetiology of bladder cancer and must be

confirmed on a larger study.

Although filter is effective in reducing the amounts of

PAHs and nicotine, it is less effective to retain volatile

carcinogenic compounds such as TSNs and aromatic

amines so that smokers are more exposed to these potent

carcinogens. The users of cigarette with filter increase

the smoking frequency and inhales more deeply, retain-

ing smoke longer. This lead as a consequence to a higher

deposition of carcinogens smokes in all vascular body

regions. These carcinogens undergo biotransformation to

give active carcinogens which are able to form ADN

adducts initiating the first steps of cancer process. In-

creased use of cigarette with filter associated to the po-

lymorphic CYP1A2 enzyme activity could therefore be a

main cause in the bladder cancer increase.

It appears that cigarette with filter is not less danger-

ous than the plain cigarette as expected. The new smok-

ing behaviour is involved in the increase incidence of

F. B'chir et al. / Health 3 (2011) 613-619

618

many aggressive cancer forms such as AD of the lung

and bladder cancer. In addition, the introduction of ciga-

rette with filter lead to an increase over time in the

number of cancers localization attributed to smoking [15,

36].

Finally, cigarette with filter and more generally smok-

ing is today a major public health problem and smoking

cessation remains the primary preventive way fo r to ba c co

related-cancers and pathologies.

REFERENCES

[1] Parkin, D.M., Pisani, P. and Ferlay, J. (1994) At least one

of seven cases of cancer is caused by smoking. Global

estimate for 1985. International Journal of Cancer, 59,

494-504. doi:10.1002/ijc.2910590411

[2] Pelluchi, C., Bosetti, C., Negri, E., Malvezzi, M. and La

Vecchia, C. (2006) Mechanisms of disease: The epidemi-

ology of bladder cancer. Nature Clinical Practice Urol-

ogy, 3, 327-340. doi:10.1038/ncpuro0510

[3] Baris, D. et al. (2009) A case-control study of smoking

and bladder cancer risk: Emergent patterns over time.

Journal of the National Cancer Institute, 101, 1553-1561.

doi:10.1093/jnci/djp361

[4] Boffetta, P. (2008) Tobacco smoking and risk of bladder

cancer. Scandinavian Journal of Urology and Nephrol-

ogy, 42, 45-54. doi:10.1080/03008880802283664

[5] Samanic, C., Kogevinas, M., Dosemeci, M., Malats, N.,

Real, F.X., Garcia-Closas, M., Serra, C., Carrato, A.,

Garcı´a-Closas, R., Sala, M., Lloreta, J., Tardon, A.,

Rothman, N. and Silverman, D.T. (2006) Smoking and

Bladder Cancer in Spain: Effects of Tobacco Type, Tim-

ing, Environmental Tobacco Smoke, and Gender. Cancer

Epdemio Markers, 15, 1345-1354.

[6] Van Hemelrijck M. J. J., Michaud, D.S., Connolly, G.N.

and Kabir, Z. (2009) Tobacco use and bladder cancer

patterns in three western European countries. Journal of

Public Health, 31, 335-344. doi:10.1093/pubmed/fdp062

[7] Raman, J.D. , Messer, J. , Sielatycki, J.A. and Hollenbeak,

C.S. (2010) Incidence and survival of patients with car-

cinoma of the ureter and renal pelvis in the USA, British

Journal of Urology International, 107, 1059-1064.

[8] Alberg, A.J. and Hebert, J.R. (2009) Cigarette Smoking

and Bladder Cancer: A New Twist in an Old Saga?

Journal of the National Cancer Institute, 101, 1525-1526.

doi:10.1093/jnci/djp385

[9] López, A.G., González, C.A., Errezola, M., Escolar, A.,

Izarzugaza, I., Nebot, M. and Riboli, E. (1991) Tobacco

smoke inhalation pattern, tobacco type, and bladder can-

cer in Spain. American Journal of Epidemiology, 134,

830-839.

[10] Hoffmann, D., Rivenson, A., Chung, F.L. and Wynder,

E.L. (1993) Potential inhibitors of tobacco carcinogene-

sis. Annals of the New York Academy of Sciences, 28,

140-160. doi :1 0.1111 /j .1749-6632.1993.tb39169.x

[11] Arnaud, M.J. (1993) Metabolism of caffeine and other

components of coffee. In: Garattini, S. Ed., Caffeine,

Coffee and Health, Raven Press, New York.

[12] B’chir, F., Laouani, A., Ksibi, S., Arnaud, M.J. and Sa-

guem, S. (2007) Cigarette filter and the incidence of lung

adenocarcinoma among Tunisian population. Lung can-

cer Amsterdam Netherlands, 57, 26-33.

doi:10.1016/j.lungcan.2007.01.034

[13] Lilienfeld, A.M., Levin, M. and Moore, G.E. (1956) The

association of smoking with cancer of the urinary bladder

in humans. Archives of Internal Medicine, 98, 129-135.

[14] U. S. Department of Health and Human Services. (2004)

The Health Consequences of Smoking, A Report of the

Surgeon General, Atlanta.

[15] Gandini, S. et al. (2008) Tobacco smoking and cancer: A

meta-analysis. International Journal of Cancer, 122,

5-64. doi:10.1002/ijc.23033

[16] Gough, K.R., Read, A.E., McCarthy, C.F. and Waters,

A.H. (1963) Megaloblastic anaemia due to nutritional

deficiency of folic acid . QJM, 32, 243-256.

[17] Chanarin, I., MacGibbon, B.M., O’Sullivan, W.J. and

Mollin, D.L. (1959) Folic-acid deficiency in pregnancy.

The pathogenesis of megaloblastic anaemia of pregnancy.

Lancet, 2, 634-639. doi:10.1016/S0140-6736(59)91409-6

[18] Pavanello, S., Mastrangelo, G., Placidi, D., Campagna,

M., Pulliero, A., Carta, A., Arici, A. and Porru, S. (2010)

CYP1A2 polymorphisms, occupational and environ-

mental exposures and risk of bladder cancer. European

Journal of Epidemiology, 25, 491-500.

doi:10.1007/s10654-010-9479-8

[19] Van der Boon J. (2001) Low-tar ﬁlter cigarettes and an

aggressive type of lung cancer. Lancet Oncology, 2, 255.

doi:10.1016/S1470-2045(00)00310-7

[20] Hoffmann, D., Rivenson, A., Murphy, S.E., Chung, F.L.,

Amin, S. and Hecht, S.S. (1993) Cigarette smoking and

adenocarcinoma of the lung: The relevance of nicotine-

derived N-nitrosamines. Journal of Smoking Related

Disorder, 4, 165-189.

[21] Wogan, G.N., Hecht, S.S., Felton, J.S., Conney, A.H. and

Loeb, L.A. (2004) Environmental and chemical carcino-

genesis. Seminars in Cancer Biology, 14, 473-486.

doi:10.1016/j.semcancer.2004.06.010

[22] Morabia, A. and Wynder, E.L. (1991) Cigarette smoking

and lung cancer cell types. Cancer, 68, 2074-2048.

doi:10.1002/1097-0142(19911101)68:9<2074::AID-CNC

R2820680939>3.0.CO;2-X

[23] Wald, N., Idle, M. and Smith, P.G. (1977) Carboxy-

haemoglobin levels in smokers of filter and plain ciga-

rettes. The Lancet, 1, 110-112.

doi:10.1016/S0140-6736(77)91702-0

[24] Lubin, J.H., Alavanja, M.C.R., Caporaso, N., Brown,

L.M., Brownson, R.C., Field, R.W., Garcia-Closas, M.,

Hartge, P., Hauptmann, M., Hayes, R.B., Kleinerman, R.,

Kogevinas M, Krewski D, Langholz B, Le tourneau E G,

Ly nch. C.F, Malats, N., Sandler, N.P., Schaffrath-Rosario,

A., Schoenberg, J.B., Silverman, D.T., Wang, Z.,

Wichmann, H.E., Wilcox, H.B. and Zielinski, J.M. (2007)

Cigarette smoking and cancer risk: Modeling total expo-

sure and intensity. American Journal of Epidemiology,

166, 479-489. doi:10.1093/aje/kwm089

[25] Hoffmann, D., Brunnemann, K.D., Prokopczyk, B. and

Djordjevic, M.V. (1994) Tobacco-specific N-nitrosamines

and Areca-derived N-nitrosamines: Chemistry, biochem-

istry, carcinogenicity and relevance to humans. Journal

of Toxicology and Environmental Health, 41, 1-52.

doi:10.1080/15287399409531825

[26] Hecht, S.S., Isaacs, S. and Trushin, N. (1994) Lung tu-

mor induction in A/J mice by the tobacco smoke carcin-

F. B'chir et al. / Health 3 (2011) 613-619

619619

gens4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone and

benzo (a) pyrene: A potentially useful model for evalua-

tion of chemopreventive agents. Carcinogenesis, 15,

2721-2725. doi:10.1093/carcin/15.12.2721

[27] Balansky, R., Ganchev, G., ltcheva, M., Steele, V.E., D’

Agostini1, F. and De Flora S. (2007) Potent carcino-

genicity of cigarette smoke in mice exposed early in life.

Carcinogenesis, 28, 2236-2243.

doi:10.1093/carcin/bgm122

[28] Landi, M.T., Sinha, R., Lang, N.P. and Kadlubar, F.F.

(1999) Human cytochrome P4501A2. In: Vineis, P.,

Malats, N., Lang, M., d’Errico, A., Caporaso, N., Cuzick,

J. and Moffetta, P., Eds., Metabolic polymorphisms and

susceptibility to cancer. IARC Scientific Publications,

Lyon, 173-195.

[29] Vineis, P., Talaska, G., Malaveille, C., Bartsch, H., Mar-

tone, T., Sithisarankul, P. and Strickland, P. (1996) DNA

adducts in urothelial cells: Relationship with biomarkers

of exposure to arylamines and polycyclic aromatic hy-

drocarbons from tobacco smoke. International Journal of

Cancer, 65, 314-316.

doi:10.1002/(SICI)1097-0215(19960126)65:3<314::AID

-IJC6>3.0.CO;2-2

[30] Bonser, G.M., Bradshaw, L., Clayson, D.B. and Jull, J.W.

(1956) A further study of the carcinogenic properties of

ortho hydroxy-amines and related compounds by bladder

implantation in the mouse. British Journal of Cancer, 10,

539-546. doi:10.1038/bjc.1956.63

[31] Lee, S.W., Jang, I.J., Shin, S.G., Lee, K.H., Yim, D.S.,

Kim, S.W., Oh, S.J. and Lee, S.H. (1994) CYP1A2 activ-

ity as a risk factor for bladder cancer. Journal of Korean

Medical Science, 9, 482-489.

[32] Guengerich, F.P. and Shimada, T. (1991) Oxidation of

toxic and carcinogenic chemicals by human cytochrome

P-450 enzymes. Chemical Research in Toxicology, 4,

391-407. doi:10.1021/tx00022a001

[33] Kamataki, T., Fujita, K., Nakayama, K., Yamazaki, Y.,

Miyamoto, M. and Ariyoshi, N. (2002) Role of human

cytochrome P450 (CYP) in the metabolic activation of

nitrosamine derivatives: Application of genetically engi-

neered Salmonella expressing human CYP. Drug Me-

tabolism Reviews, 34, 667-676.

doi:10.1081/DMR-120005668

[34] Landi, M.T., Zocchetti, C., Bernucci, M., Kadlubar, F.F.,

Tannenbaum, S., Skipper, P., Bartsch, H., Malaveille, C.,

shields, P., Caporaso, N. and Vinei, P. (1996) Cyto-

chromeP4501A2: Enzyme Induction and Genetic Control,

Determining 4-aminobiphenyl-hemoglobin Adduct Lev-

els. Cancer Epidemiology, Biomarkers & Prevention, 5,

693-698.

[35] Le Marchand, L., Hankin, J.H., Wilkens, L.R., Pierce,

L.M., Franke , A., Kolo nel, L. N., Seifried, A. , Custer, L.J.,

Chang, W., Lum, J.A. and Donlon, T. (2001) Combined

Effects of Well-done Red Meat, Smoking, and Rapid

N-Acetyltransferase 2 and CYP1A2 Phenotypes in In-

creasing Colorectal Cancer Risk. Cancer Epidemiology,

Biomarkers & Prevention, 10, 1259-1266.

[36] Working group on the Evaluation of Carcinogenic Risks

to Humans. (2004) Tobacco smoke and involuntary

smoking. IARC Monographs on the Evaluation of Car-

cinogenic Risks to Humans, Lyon, 1-1438.