Descriptive analysis of estrogen receptor (ER)‐negative, progesterone receptor (PR)‐negative, and HER2‐negative invasive breast cancer, the so‐called triple‐negative phenotype

Abstract BACKGROUND. Tumor markers are becoming increasingly important in breast cancer research because of their impact on prognosis, treatment, and survival, and because of their relation to breast cancer subtypes. The triple‐negative phenotype is important because of its relation to the basal‐like subtype of breast cancer. METHODS. Using the population‐based California Cancer Registry data, we identified women diagnosed with triple‐negative breast cancer between 1999 and 2003. We examined differences between triple‐negative breast cancers compared with other breast cancers in relation to age, race/ethnicity, socioeconomic status (SES), stage at diagnosis, tumor grade, and relative survival. RESULTS. A total…