Clinical and prognostic profile of Her2neu positive (non-luminal) intrinsic breast cancer subtype: Comparison with Her2neu positive luminal breast cancers

Objective: Her2neu receptor is proto-oncogene which can be over-expressed in both luminal and non-luminal breast cancers. In the present study, we aimed to compare the prognostic and predictive factors like tumor grade, T-stage, N-stage and ki67 index in Her2neu intrinsic breast cancer subtype with Her2neu over-expressed luminal breast cancers. Results: 801 (41%) cases were Her2neu positive; out of which, 418 cases (52.2%) showed ER positivity and thus were classified as Her2neu positive luminal cancers whereas 383 cases (47.8%) were ER and PR negative and therefore were labeled as intrinsic Her2neu subtype (non-luminal). Her2neu positive (non-luminal) cancers were significantly associated with higher grades and Ki67 proliferative index compared to Her2neu positive luminal cancers. On the other no significant association was noted in T-stage and N-stage. We found a high frequency of her2neu positivity in our studied population of breast cancer. Moreover, association of her2neu positive (non-luminal) breast cancers with higher grade and ki67 index indicates a predictive value of ER/PR positivity in her2neu positive breast cancers. On the other hand, lack of association with respect to T and N stage, signifies no prognostic benefit of ER/PR in her2neu positive breast cancers.