Tumor suppressor genes encode proteins that normally restrain cell division. Mutation in one or more of these genes can lead to tumor formation.

______特效特别擅长处理含有透明区域的图片，如烟雾、阴影、玻璃和水等。 A: Color difference B: Color Range C: Extract D: pill Suppressor

Which of the following statements is right? A: RB exerts anti-proliferative effects by controlling the G1-to-S transition of the cell cycle B: RB is a key positive regulator of the cell cycle C: The TP53 was the first tumor suppressor gene to be discovered by the study of retinoblastoma D: Malignant transformation is only derived from one of the normal RB alleles inactivated