The activity of Rb proteins is controlled by post-translational modifications, especially through phosphorylation.Acetylation of Rb2/p130 was reported recently in NIH3T3 cells but its physiological relevance in cell cycle controland tumorigenesis is still unknown. Efforts are underway to investigate possible interplay between Rb2/p130phosphorylation and acetylation. Here we hypothesized that Rb2/p130 acetylation, like p53 acetylation, may playa role in development of the tumor phenotype. The proposed hypothesis regarding acetylation of Rb2/p130 intumor VS normal cells was found to be true in our case study of 36 tumor samples. Statistical analysis of resultssuggest strong correlation among Rb2/p130 acetylation and cancer phenotype.