The purpose of this study is to define new genes for family risks of developing colon cancer.

Colorectal cancer is one of the most significant causes of cancer morbidity and mortality in the United States. In 1997, approximately 130,000 men and woman were diagnosed with colorectal cancer (fourth most common cancer site) and approximately 55,000 died of this disease (second most common cause of cancer deaths); (Cancer Facts & Figures, 1997).

Genetic factors clearly contribute to the etiology of colorectal cancer. Because there is evidence to suggest genetically determined susceptibility to colorectal cancer exists in a proportion of newly diagnosed cases each year, we are conducting a study to identify new genes that are associated with an increased susceptibility to familial colorectal cancer by analysis of families with a clustering of colorectal cancers.

Inclusion Criteria:

• Age 18 years or greater
• Able to provide informed consent
• Any family in which a minimum of two first-degree relatives either are, or have previously been, affected with primary colorectalcancer. These "minimum inclusion criteria" must be met within three generations of the proband or kindreds in which colorectal cancer and lymphoma or renal cell cancer are present or in kindreds in which lymphoma alone or lymphoma and renal cell cancer are present

Exclusion Criteria:

• Age less than 18 years
• Family not at increased risk for familial colorectal cancer (see Section 4.1)
• Family with a hereditary polyposis syndrome (e.g. classic FAP)
• Not able to provide informed consent

families seen at MSKCC with at least two first-degree relatives affected with colorectal cancer