Blood type, hormone receptor status, HER2/neu status, and survival in breast cancer: a retrospective study exploring relationships in a phenotypically well-defined cohort.

PURPOSE: Altered glycosylation has been associated with oncogenic potential. Relationships of blood types (where expression is due to glycosylation pattern) and HER2/neu (where expression arises due to altered glycosylation) and breast cancer-associated markers like estrogen receptor/progesterone receptor (ER/PR) were examined and related to outcomes in patients with breast cancer.
METHODS: A population-based retrospective study of 426 surgical breast cancer patients examined relationships between (1) patient characteristics, (2) breast tumor characteristics, and (3) outcomes of women diagnosed at the same medical center over a 10-year period relative to specific molecules defined by glycosylation patterns (eg. blood group, HER2/neu) and (4) ER/PR status.
RESULTS: Following stratification by blood group, subjects exhibited significant differences in tumor size with persons in blood groups A and B having greater numbers of tumors ≤ 2 cm and those with blood types AB and O having tumors >2 cm. After adjusting for age, disease stage, and treatment with trastuzumab, tamoxifen, or aromatase inhibitors, no significant differences were observed in 5-year overall and disease-free survival based on blood type grouping. Blood group B was over-represented among the breast cancer cohort compared to the reference population, while blood group AB was under-represented.
CONCLUSION: No significant differences were observed in overall and disease-free survival based on blood group. No correlation was noted between HER2/neu, ER or PR status, and blood group type. Among this cohort, HER2/neu positivity was less than 20% and correlated with a 5-year disease-free survival rate ≥ 75% and overall survival of >80% across all blood groups.