Is Colo-rectal cancer cosed by generic defect leading to polyps?

Risk factors
Factors that may increase your risk of colon cancer include:

Age. About 90 percent of people diagnosed with colon cancer are older than 50. Colon cancer can occur in younger people, but it occurs much less frequently.
A personal history of colorectal cancer or polyps. If you've already had colon cancer or adenomatous polyps, you have a greater risk of colon cancer in the future.
Inflammatory intestinal conditions. Long-standing inflammatory diseases of the colon, such as ulcerative colitis and Crohn's disease, can increase your risk of colon cancer.
Inherited disorders that affect the colon. Genetic syndromes passed through generations of your family can increase your risk of colon cancer. These syndromes cause only about 5 percent of all colon cancers. One genetic syndrome called familial adenomatous polyposis (FAP) is a rare disorder that causes you to develop thousands of polyps in the lining of your colon and rectum. People with untreated FAP have a greater than 90 percent chance of developing colon cancer by age 45. Another genetic syndrome, hereditary nonpolyposis colorectal cancer (HNPCC), also called Lynch syndrome, is more common than FAP. People with HNPCC have an increased risk of colon cancer and tend to develop colon cancer at an early age. Both FAP and HNPCC can be detected through genetic testing. Talk to your doctor about whether your family history suggests you have a risk of these conditions.
Family history of colon cancer and colon polyps. You're more likely to develop colon cancer if you have a parent, sibling or child with the disease. If more than one family member has colon cancer or rectal cancer, your risk is even greater. In some cases, this connection may not be hereditary or genetic. Instead, cancers within the same family may result from shared exposure to an environmental carcinogen or from diet or lifestyle factors.
Diet. Colon cancer and rectal cancer may be associated with a diet low in fiber and high in fat and calories. Research in this area has had mixed results. Some studies have found an increased risk of colon cancer in people who eat diets high in red meat and processed meats.

People who eat a diet similar to that of Western countries, such as the United States and Europe, have a higher risk of developing colon cancer than do people who eat diets typically seen in developing countries. When people move from a developing country to a Western country and adapt to the Western diet, their risk of colon cancer increases. Although many studies have tried to identify what part of the Western diet may cause colon cancer, the answer remains unknown.

A sedentary lifestyle. If you're inactive, you're more likely to develop colon cancer. This may be because when you're inactive, waste stays in your colon longer. Getting regular physical activity may reduce your risk.
Diabetes. People with diabetes and insulin resistance may have an increased risk of colon cancer.
Obesity. People who are obese have an increased risk of colon cancer and an increased risk of dying of colon cancer when compared with people considered normal weight.
Smoking. People who smoke cigarettes may have an increased risk of colon cancer. They may also have an increased chance of dying of colon cancer.
Alcohol. Heavy use of alcohol may increase your odds of colon cancer.
Growth hormone disorder. Acromegaly, an uncommon disorder that causes an excess of growth hormone in your body, may increase your risk of colon polyps and colon cancer.
Radiation therapy for cancer. Radiation therapy directed at the abdomen to treat previous cancers may increase the risk of colon

No.

It's due to your diet and environment.

There are several types of intestinal polyps that you might see. But not all of them will lead to colorectal cancer. Adenomatous polyps are most commonly associated with the development of cancers. Other factors that may predispose you for cancers include low fiber in the diet, high consumption of meats as well as processed meats.