Breast Cancer Phenotype and Prognosis

prognosis are determined by a multitude of factors that include, but are not limited to, age; stage of cancer; tumour characteristics such as estrogen receptor (er) status, progesterone receptor (pr) status, and human epidermal growth factor receptor 2 (her2/ neu) status; and histologic grade. Gene expression profiling has revealed new classifications of breast cancer: two are er-positive (luminal A and B), and two are er-negative (her2-positive and basal-like) 1. Basal-like tumours usually demonstrate low levels of estrogen and her2 gene expression, strongly correlating with triple-negative breast cancer (tnbc), which is er-, pr-, and her2-negative. Unfortunately, gene profiling is not clinically available at this time, and many investigators allocate patients to groups that can be identified using immunohistochemistry. Triple-negative breast cancer has been associated with younger age groups and patients presenting with a higher stage of disease 2, and it is thought to have a worse prognosis 3. More recent studies 4,5 have reported that the tumour size at presentation is the most important predictor of survival in tnbc. It is important that the differences in characteristics between patients with tnbc and with other breast cancers be further investigated. The purpose of the present study was therefore to compare survival rates and prognostic factors between patients with tnbc and those with other breast cancers.