Premenopausal Breast Cancer Risk Factors and Associations with Molecular Subtypes: A Case-Control Study

Table 6

Prevalence of different breast cancer molecular subtypes ().

Molecular subtype classification		%
Luminal A	45	26.5
Luminal B	22	12.9
HER2 enriched	25	14.7
Triple negative	22	12.9
Unclassified	56	32.9

Luminal A: ER+/PR+, HER2/Neu negative; luminal B: ER+/PR+, HER/Neu positive; HER2 enriched: ER-/PR-, HER2/Neu positive; triple negative: ER-/PR-, HER2/Neu negative. Unclassified: any other combination and equivocal HER2/Neu. It is important to note that for the purpose of this study, tumors with equivocal HER2/Neu status were considered “unclassified.” In fact, if the IHC result is 3+, the cancer is HER2/Neu positive. If the IHC result is 1+, the cancer is HER2/Neu negative. However, if the result is 2+, the HER2/Neu status is not clear (equivocal) and needs further testing by FISH to clarify the result. Unfortunately, FISH technology is not available in the country.