Shorter survival-times following adjuvant endocrine therapy in oestrogen- and progesterone-receptor positive breast cancer overexpressing HER2 and/or with an increased expression of vascular endothelial growth factor.
OBJECTIVE
To investigate the possible correlation between expression of HER2 and vascular endothelial growth factor (VEGF), and to determine the predictive value of these factors in patients receiving adjuvant endocrine therapy including the group with a breast cancer (BC) positive for both oestrogen receptor (ER) and progesterone receptor (PgR).


METHODS
By enzyme immuno-sorbent assays (ELISA) tumour levels of HER2 and VEGF proteins were determined in 679 consecutive primary BC patients, median age 63 years, median follow-up time 92 months. A total of 404 patients received adjuvant endocrine therapy, mainly tamoxifen, out of them 295 had an ER and PgR positive BC. In 160 patients, HER2 status was also determined by immunohistochemistry (IHC) using the monoclonal antibody CB11.


RESULTS
Overexpression of HER2 by IHC was found in 15% of the patients. Overexpression of HER2 by ELISA correlated with HER2 by IHC (P < 0.001) and a higher VEGF expression (P = 0.004). Patients receiving adjuvant endocrine therapy with high VEGF (RFS P = 0.0087, BCCS P = 0.0012) or over-expressing HER2 (RFS P = 0.0116, BCCS P = 0.0036) had significantly shorter survival. Factors retaining statistical significance in multivariate analyses for recurrence-free survival (RFS) were nodal status (P < 0.001), tumour size (P = 0.005) and VEGF (P = 0.032) and for breast cancer corrected survival (BCCS) nodal status (P < 0.001), tumour size (P = 0.001), ER status (P = 0.022), and VEGF (P = 0.016). Both factors were significantly correlated with survival in the group with a BC positive for both ER and PgR; VEGF (RFS P = 0.0177, BCCS P = 0.0321) and HER2 (RFS P = 0.0143, BCCS P = 0.0311). In multivariate analyses, nodal status (P < 0.001) and VEGF (P = 0.021) were independent factors for RFS. Nodal status (P < 0.001) and tumour size (P = 0.016) retained independent factors for BCCS. Combined analysis identified a high-risk group (HER2 positive and high VEGF) with significantly reduced survival.


CONCLUSIONS
The results from this retrospective analysis suggest that overexpression of HER2 and higher VEGF expression may add information on patient's outcome after adjuvant endocrine therapy in ER and PgR positive BC.
Linderholm
B
B
Karolinska Biomic Centre (KBC), Karolinska Institute and University Hospital, SE-161 67 Stockholm, Sweden. barbro.linderholm@ki.se
Bergqvist
J
J
Hellborg
H
H
Johansson
U
U
Linderholm
M
M
von Schoultz
E
E
Elmberger
G
G
Skoog
L
L
Bergh
J
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality*; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy / Q000378:metabolism / Q000401:mortality; D018275:Carcinoma, Lobular / Q000188:drug therapy / Q000378:metabolism / Q000401:mortality; D017024:Chemotherapy, Adjuvant; D017326:Clinical Trials, Phase III as Topic; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D017273:Goserelin / Q000627:therapeutic use; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000401:mortality; D016032:Randomized Controlled Trials as Topic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012189:Retrospective Studies; D015996:Survival Rate; D013629:Tamoxifen / Q000627:therapeutic use; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D018931:Antineoplastic Agents, Hormonal; D017273:Goserelin; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen; D042461:Vascular Endothelial Growth Factor A; C467484:VEGFA protein, human