Answer to Question 1
All cancer is caused by an alteration in specific regions of the DNA that code for the many proteins that regulate the cell cycle. About 5 of cancer-causing DNA alterations are inherited from our parents at conception. During our lifetime external factors can initiate or promote cancer. These include tobacco use, poor diet, and exposure to harmful chemicals, radiation, and infectious organisms. There are also internal factors such as hormones, immune conditions, and mutations that occur spontaneously and initiate cancer.
Answer to Question 2
carotenodermia