RB1 and ovarian carcinoma: In the context of high levels of P-RB, this criteria should indicate that either 14-3-3 σis dysfunctional or that active CDC2 is uninhibited, perhaps due to methylated 14-3-3 σ or inhibition of CDC2 degradation [42] We observed that of the 57 ovarian cancer cell lines represented in the RPPA, 28 cell lines (49%) showed high levels of 14-3-3 σ (Figure 6A) of which 16 cell lines (28%) also had increased P-RB, corresponding to the O2 insensitivity pattern we have described.