When the cell cycle is disrupted, cells can grow and divide uncontrollably. what makes cancer cells different from normal, non-cancerous cells?

When an oncogene is turned on and is not balanced through suppression of tumor suppressor gene, the normal cells become cancerous and divides unregulated. Normal cells differentiate while cancer cells do not. Additionally, while normal cells respond to endocrine and paracrine signals from neighboring cells, cancer cells do not. Cancer cells have malfunctioned apoptosis process due to a malfunctioned p53 tumor suppressor gene. Therefore they continue to divide even when they have damage to their DNA. Cancer cells metastasize because, unlike normal cells, they do not produce an adhesive molecule that allows the cells to adhere to one another to form tissue.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.