Of interest, while ATRA significantly decreased RARα and RXRα expression in SKMES-1 (p = 0.03) and H1299 (p = 0.0079) PT cells, respectively, there was a significant increase in the tumour suppressor and major target gene of retinoid action, RARβ, in H1299 CisR cells (p = 0.0326) relative to untreated controls. This evidence concerns the gene RARB and neoplasm.