RARRES1 and breast cancer: While we and others have demonstrated a clear role for ALDH1A3 in initiating retinoid signaling and affecting the expression of RARE-containing genes including RARβ, the tumor suppressor gene RARRES1, and tissue transglutaminase8,42,78, the sole contribution of ALDH1A3 as a retinaldehyde dehydrogenase in breast cancer and the stem cell phenotype (cancerous or non-cancerous) may be overstated8,41,44,79–81.