Patent ID: 7867717

Claim:
A method of screening for hereditary colorectal cancer or a predisposition to hereditary colorectal cancer in an organism, said screening method comprising: (a) isolating a biological sample containing normal cells from said organism; (b) immunologically quantitating the levels of full-length PMS1 and full-length PMS2 in said normal cells; (c) calculating the ratio of the level of full-length PMS1 in said normal cells, to the level of full-length PMS2 in said normal cells; and (d) determining whether the ratio calculated in step (c) reflects about a 50% decrease from a normal level of PMS1 or PMS2, wherein said normal level of PMS1 or PMS2 is determined in individuals unaffected by said hereditary colorectal cancer or predisposition to hereditary colorectal cancer; whereby if the ratio calculated in step (c) indicates that there is about a 50% decrease from said normal level of either full-length PMS1 or full-length PMS2 in said normal cells, determining that the subject organism has hereditary colorectal cancer or has a predisposition to hereditary colorectal cancer.