p53 mutations in primary and metastatic tumors and circulating tumor cellsfrom colorectal carcinoma patients

Circulating tumor cells could provide a relatively non-invasive and repeata ble source of information about tumor cell genotype that might influence tr eatment and estimation of prognosis. We developed a technique for identifyi ng p53 mutations in tumor cells isolated from the peripheral venous blood o f colorectal cancer patients and compared the prevalence and position of th ese mutations with multiple solid tumor samples from the same patient. We u sed immunomagnetic beads to isolate tumor cells, reverse transcriptase-nest ed polymerase chain amplification of the coding region between exons 4 and 9 within the p53 gene, and automated gene sequencing. Nineteen p53 mutation s were detected in solid tumor samples from 19 of 41 colorectal carcinoma p atients. An identical p53 mutation was invariably present in all samples fr om primary and metastatic colorectal tumor biopsies within the same patient , p53 mutations were detected in peripheral blood from 8 of these 19 patien ts with p53-mutated solid tumors. Where identified, the pattern of mutation in peripheral blood samples was invariably the same as in matching solid t umor samples. A single colorectal carcinoma biopsy provided reliable p53 ge ne mutational information in colorectal carcinoma. Detection of this p53 mu tation in tumor cells from peripheral blood was achieved with an approach b ased on cell selection for epithelial characteristics, reverse transcriptio n-PCR, and gene sequencing.