TITLE:
Inverted Apical CD24 and Weak EZH2 Expressions Are Phenotypic Characteristics of Pure Invasive Micropapillary Carcinoma of the Breast
AUTHORS:
Nadège Gruel, Aurélie Cédenot, Marion Richardson, Paul Fréneaux, Jaydutt Bhalshankar, Thierry Dubois, Xavier Sastre-Garau, Olivier Delattre, Anne Vincent-Salomon
KEYWORDS:
CD44; CD24; ALDH1; EZH2; Invasive Micropapillary Breast Carcinoma
JOURNAL NAME:
Open Journal of Pathology,
Vol.3 No.2,
April
25,
2013
ABSTRACT: Invasive micropapillary carcinomas (IMPC) of the breast
account for less than 2% of all breast cancers and have been recently described
as luminal B carcinomas. CD24, CD44, ALDH1 and EZH2 are commonly used as
stem-cell markers that display differential expression as a function of stage
and molecular type, but their pattern of expression according to this rare
histological type remains poorly defined and unknown for EZH2. We assessed
expression of these markers in a series of 28 micropapillary breast carcinomas
and compared the results with those obtained in a series of luminal A (27
cases) and B (34 cases) invasive carcinomas not otherwise specified (IC-NST).
CD24 and CD44 were expressed in most cases. However, CD24 was expressed at the
inverted apical membrane in 85% of invasive micropapillary carcinoma and at the
apical pole of gland-forming cells in 45% of luminal A (p-val = 6.8 × 10－4)
and 13% of luminal B cases (p-val = 1.1 × 10－7). ALDH1 was
expressed in the stroma in most tumors, but in only 25%, 11% and 15% in epithelial
cells of IMPC, luminal A and B IC-NST, respectively.
Nuclear expression of EZH2 was not observed in luminal A tumors, and was
detected in 35% (12/34) of luminal B carcinomas (p-val = 6.1 × 10－3) and only 4% (1/28) of invasive
micropapillary carcinomas. This series shows that invasive micropapillary
carcinomas harbor a CD24-positive inverted apical pole associated with weak
EZH2 expression, phenotypical characteristics that distinguish this entity from
other luminal carcinomas.