Cancer heterogeneity is a putative mechanism of resistance in a broad array of cancer pathologies. The probabilities of macro-evolutionary changes which initiate resistance are low, yet resistance remains nearly ubiquitous. We have observed spontaneous heterogeneity in triple negative breast cancer cells on short time-scales in surface markers stratifying differentiation of the normal breast. We hypothesize these micro-evolutionary dynamics play a buffer role in initial response to therapy. We are using an information theory formalism to quantify the micro evolutionary dynamics in triple negative breast cancer.