Low- and high- agressive genetic breast cancer subtypes and significant survival gene signatures

We characterize three small gene signatures derived consequently from the original 232-gene breast cancer aggressiveness signature which could improve biological classification and clinical assignment of ~50% of breast cancer patients having histologic grade 2 tumors . Here, we develop a novel approach to identify small gene signatures providing statistically reliable, biological important and clinical significant molecular markers.We consider three small molecular signatures which strongly represent three specific groups of genes related to (i) cell cycle /mitosis, (2) chromosome segregation and micro-tubular formation, (3) cell-cell communication, extracellular/immune signaling, and RNA binding. These results shed light on underlined biological mechanisms of low-aggressive and high-aggressive human breast cancer phenotypes and support our suggestion that re-classification of grade 2 breast tumors onto tumor grade 1-like and tumor grade 3-like subtypes can be related to two genetically and clinically distinct cancer types.