In these epithelial-derived tumors the SH2-containing SHIP1 isoforms are not thought to be expressed; however, an internal promoter is active in cancer stem cell populations present in epithelial tumors suggesting the s-SHIP stem cell-specific isoform of SHIP1 [124] may be expressed and contribute to tumor stem cell survival [125,126,127]. The gene discussed is INPP5D; the disease is neoplasm.