RB1 and breast carcinoma: Previous studies have shown that CDK6 can activate the CDK‐cyclinD‐Rb‐E2F pathway, enabling the transcription factor E2F to activate tumor gene transcription and force the cell cycle to enter the S phase, thereby promoting the growth, migration, and metastasis of various malignant tumors, including pancreatic neuroendocrine,16 cervical,17 bladder,18 gastric,19 epithelial ovarian,20 and breast carcinomas.21