The role of four oestrogen-responsive genes, pLIV1, pS2, pSYD3 and pSYD8, in predicting responsiveness to endocrine therapy in primary breast cancer.
The expression of four oestrogen-responsive genes in 118 immunohistochemically defined primary breast tumours has been determined by northern analysis. While all the genes are induced by oestrogen in oestrogen receptor (ER)-positive cell lines, their behaviour is different in breast tumour biopsies. This behaviour can be divided into two groups; the first containing the genes, pLIV1 and pLIV2 (pS2), which both show a significant association with ER status (P = 0.001) and a corresponding inverse relationship with epidermal growth factor receptors (EGFR) (P = 0.01 and P = 0.08, respectively). In addition, the mRNA levels of both pLIV1 and pS2 are greater in ER-positive compared to ER-negative disease (P = 0.001). While a small number of ER-negative tumours were positive for either pLIV1 (12%) or pS2 (9%), we failed to observe co-expression of pLIV1 and pS2 in ER-negative disease. In ER-positive disease, four tumour populations were identified; ER+pLIV1-pS2-, ER+pLIV1-pS2+, ER+pLIV1+pS2- and ER+pLIV1+pS2+. Interestingly, the levels of pLIV1 and pS2 when co-expressed were significantly greater in ER+pLIV1+pS2+ tumours compared to either of the ER+pLIV1+pS2- (P = 0.03) or ER+pLIV1-pS2+ (P = 0.01) mixed phenotypes. Unlike pLIV1 and pS2, pSYD3 and pSYD8 belong to a group of genes which are expressed in the majority of tumours regardless of ER and EGFR status. However, lower pSYD8 mRNA levels were detected in moderately EGFR-positive disease (P = 0.06) while both pSYD3 positivity (P = 0.01) and mRNA levels (P = 0.001) were increased in highly proliferating tumours as shown by Ki67 immunostaining. These genes provide additional markers which, in conjunction with other parameters, may help to determine the likelihood of a given tumour to respond to endocrine therapy.
Breast Cancer Laboratory, Tenovus Cancer Research Centre, University of Wales College of Medicine, Heath Park, Cardiff, U.K.
D L
DL
Manning
R A
RA
McClelland
J M
JM
Gee
C M
CM
Chan
C D
CD
Green
R W
RW
Blamey
R I
RI
Nicholson
D014408:Biomarkers, Tumor / Q000235:genetics; D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy / Q000235:genetics*; D066246:ErbB Receptors / Q000032:analysis; D004967:Estrogens / Q000627:therapeutic use*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins / Q000032:analysis; D009687:Nuclear Proteins / Q000032:analysis; D009857:Oncogenes; D012334:RNA, Neoplasm / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis
D014408:Biomarkers, Tumor; D004967:Estrogens; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D012334:RNA, Neoplasm; D011960:Receptors, Estrogen; D066246:ErbB Receptors