RB1 and Kaposi's sarcoma: Among 10 proteins involved in cell cycle, apoptosis, and cell survival, Rb and phosphorylated Rb (pRb) were more highly expressed in the KS group (97% and 92%, respectively), when compared to their expression in BG, HE, and AS (50%–92% and 62%–68%, p < 0.001 and p = 0.009, respectively, Table 1 and Figure 1a).