RB1 and cancer: Interestingly, frequencies of RB1/TP53 co-mutations were also found in many types of sarcomas, such as pleomorphic liposarcoma, leiomyosarcoma, myxofibrosarcoma, etc. The overall RB1/TP53 co-mutation frequencies are significantly higher in small cell carcinoma, neuroendocrine carcinoma, and sarcomas compared to the other cancer types (Figure 2c).