Takayuki Iwamoto    Department   Kawasaki Medical School  Kawasaki Medical School, Department of Breast and Thyroid Surgery,    Position   Assistant Professor
Article types	原著
Language	English
Peer review	Peer reviewed
Title	Estrogen receptor (ER) mRNA expression and molecular subtype distribution in ER-negative/progesterone receptor-positive breast cancers.
Journal	Formal name：Breast cancer research and treatment Abbreviation：Breast Cancer Res Treat ISSN code：15737217/01676806
Domestic / Foregin	Foregin
Volume, Issue, Page	143(2),pp.403-9
Author and coauthor	Mitsuya Itoh, Takayuki Iwamoto, Junji Matsuoka, Tomohiro Nogami, Takayuki Motoki, Tadahiko Shien, Naruto Taira, Naoki Niikura, Naoki Hayashi, Shoichiro Ohtani, Kenji Higaki, Toshiyoshi Fujiwara, Hiroyoshi Doihara, W Fraser Symmans, Lajos Pusztai
Authorship	2nd author
Publication date	2014/01
Summary	We examined estrogen receptor (ER) mRNA expression and molecular subtypes in stage I-III breast cancers that are progesterone receptor (PR) positive but ER and HER2 negative by immunohistochemistry (IHC) or fluorescent in situ hybridization. The ER, PR, and HER2 status was determined by IHC as part of routine clinical assessment (N = 501). Gene expression profiling was done with the Affymetrix U133A gene chip. We compared expressions of ESR1 and MKI67 mRNA, distribution of molecular subtypes by the PAM50 classifier, the sensitivity to endocrine therapy index, and the DLDA30 chemotherapy response predictor signature among ER/PR-positive (n = 223), ER-positive/PR-negative (n = 73), ER-negative/PR-positive (n = 20), and triple-negative (n = 185) cancers. All patients received neoadjuvant chemotherapy with an anthracycline and taxane and had adjuvant endocrine therapy only if ER or PR > 10 % positive. ESR1 expression was high in 25 % of ER-negative/PR-positive, in 79 % of ER-positive/PR-negative, in 96 % of ER/PR-positive, and in 12 % of triple-negative cancers by IHC. The average MKI67 expression was significantly higher in the ER-negative/PR-positive and triple-negative cohorts. Among the ER-negative/PR-positive patients, 15 % were luminal A, 5 % were Luminal B, and 65 % were basal like. The relapse-free survival rate of ER-negative/PR-positive patients was equivalent to ER-positive cancers and better than the triple-negative cohort. Only 20-25 % of the ER-negative/PR-positive tumors show molecular features of ER-positive cancers. In this rare subset of patients (i) a second RNA-based assessment may help identifying the minority of ESR1 mRNA-positive, luminal-type cancers and (ii) the safest clinical approach may be to consider both adjuvant endocrine and chemotherapy.
DOI	10.1007/s10549-013-2763-z
PMID	24337596