RB1 and neoplasm: Tumour suppressor genes, or anti-oncogenes, are genes that encode proteins that suppress malignant transformation, survival and metastatic dissemination, protecting cells from becoming cancerous by preserving the integrity of cellular DNA and regulating vital cell-cycle processes in combination with the 'genome guardian', P53. Many tumour suppressor genes have been investigated, but only P53 and retinoblastoma (pRb) are widely understood.