ERBB2 and breast cancer: As expected, while breast cancer cases of luminal and human epidermal growth factor-2 (HER-2) overexpression subtypes showed concomitant expression of PRLR with TGFβRI and TGFβRII in a range of 27.77% to 34.38% of cases, triple negative breast cancer (TNBC), the most aggressive breast cancer subtype, showed no co-expression between PRLR with either of the two TGFβ receptors (Table 1).