By the same token, due to heterogeneous expression of aldehyde dehydrogenase (ALDH), the enzyme involved in physiological RA synthesis [44], within a breast cancer cell population [45], we set out to test if breast cancer cell fate decisions may depend on both the cell context-specific transcriptional functionality of RARA and physiological endogenous RA synthesis variation. The gene discussed is LDHA; the disease is breast cancer.