Receptor status of breast cancer diagnosed during pregnancy: A literature review

[Display omitted] •Pregnancy-associated breast cancer (PABC) is reported to be frequently ER and PR negative and more often HER2 positive.•Breast cancer during pregnancy (BCdP) might differ from postpartum breast cancer, due to different hormonal influences.•We show BCdP to have an aggressive histopathologic profile, distinct from similar-age control breast cancer patients.•We defined the ER, PR and HER2 status of BCdP for comparison with other PABC subgroups (e.g., postpartum patients). The definition of PABC is inconsistently given as either breast cancer diagnosed exclusively during pregnancy, or combined with breast cancer diagnosed within six months to five years after delivery, and sometimes even longer. The longer away from the delivery date breast cancer is diagnosed, the less clear this association with pregnancy may become. Therefore, breast cancer diagnosed during pregnancy (BCdP) may not necessarily be the same disease entity as PABC. This review aims to provide an overview of BCdP receptor status, as this has not been assessed before. BCdP tumors were predominantly ER negative (56.6 %), PR negative (57.2 %) or both ER and PR negative (47.9 %). Moreover, HER2-overexpression was seen in 33.2 % of BCdP patients and 27.6 % had triple negative disease. This predominantly ER and PR negative profile with more often HER2 overexpression is aggressive and distinct from non-pregnant similar-aged patients, warranting future comparative research.