TITLE:
Statins and Breast Cancer: An Overview of the Current Situation
AUTHORS:
Sohun Moonindranath, Huiling Shen
KEYWORDS:
Statins, HMG CoA Reductase Inhibitors, Breast Cancer
JOURNAL NAME:
Advances in Breast Cancer Research,
Vol.5 No.1,
January
26,
2016
ABSTRACT: Statins [(3-hydroxy-3-methylglutaryl-coenzyme A reductase, HMG-CoA reductase,
abbreviated HMGCR) inhibitors] inhibit cholesterol synthesis and are commonly used
in the treatment and prevention of cardiovascular diseases. Preclinical and clinical
studies have shown that the drug can be effective in several cancers including breast
cancer which is the second most frequent cancer in the world and the commonest one
among women. In breast cancer cell lines statins reduce proliferation, increase
apoptosis, decrease invasion and sensitize them to radiation. Clinical trials in
breast cancer patients have shown positive outcome in terms of decreased recurrence
rate, decreased mortality and positive role as neoadjuvant agent. They may have
a particular role in treatment-resistant cases like triple-negative or inflammatory
breast cancer which have a poorer prognosis. There is also evidence of their potential
use in metastatic bone disease from breast cancer. When statins inhibit 3-hydroxy-3-methylgutaryl
CoA reductase which is the rate-limiting enzyme of the mevalonate pathway, the levels
of mevalonate as well as its downstream products are decreased. Hence cancer growth
is inhibited by reduced prenylation of CAAX proteins, N-Glycosylation of growth
factor receptors and synthesis of membrane and steroid among others. Also statins
are relatively cheap and can contribute to decrease the high cost of cancer treatment.
However studies till now have not shown any association with decreased breast cancer
incidence. In addition there are doubts regarding safety of statins when used over
a prolonged period of time. Although statins are relatively safe with myotoxicity
and hepatotoxicity being their major side effects, evidence regarding issues like
drug interactions with anti-cancer drugs is lacking.