ISL1 and lung cancer: However, several of the top genes diagnosing each subgroup have not been described in the literature for lung cancer, as the neuroendocrine marker ISL1 (insulin gene enhancer protein ISL-1) for the SCLC, the ATP11A (ATPase, class VI, type 11A) for SQ, GALE (UDP-galactose-4-epimerase) for the AD, and VAMP2 (vesicle-associated membrane protein 2/synaptobrevin 2) for the COID (see Results and Supplementary Material).