The group median expression value for 47 of the 100 genes increased monotonically from AD to SQ to SCLC subtypes, correlating with the relative lethality of the subtypes, whereas six genes exhibited the opposite, decreasing, group median trend:EPHB4, GCS1, IL4R, PMP22, RARRES2, andTAGLN2. Interestingly,EPHB4 promotes cell adhesion [31],RARRES2 is a receptor for retinoids that are known to inhibit growth and stimulate differentiation [32], andTAGLN2 is homologous toTAGLN, whose expression loss marks the Ras oncogenic transformation in epithelial cells [33]. The gene discussed is RARRES2; the disease is small cell lung carcinoma.