It was found that autofluorescence attenuation parameters of NAD(P)H coenzyme in human glioblastoma cells change significantly when exposed to both YT–Vav1+CISH–/– and YT–Vav1+B2M–/–, indicating occurrence of an early metabolic shift in tumor cells towards a less aggressive oxidative phenotype, and this is consistent with dead cells fraction increase and living cells fraction decrease in spheroid composition. This evidence concerns the gene VAV1 and neoplasm.