Solid tumors such as colorectal adenocarcinomas consist of biologically diverse cell subpopulations. Nuclear DNA content of tumor cells in colorectal carcinomas may be studied with different techniques of intranuclear DNA quantification. In the current study, the DNA ploidy of samples obtained from 68 patients with colorectal carcinoma (age ranging from 46 to 86 years, mean age 66 years), treated with radical surgery, between the years 1992 and 1995 was analyzed. DNA ploidy was assessed using a CAS 200 image analyzer and was evaluated on neoplastic tissue and undamaged healthy mucosa obtained from the edges of the surgical resection. Approximately 150-300 cells were analyzed for each sample. The aim of this study was to evaluate the prognostic significance of the polyclonal cases correlated with lymph node infiltration and disease free-survival. The pathological stage according to the TNM classification was compared to ploidy: an increase in multiple stemlines was observed in stage III cases, i.e., a progression towards aneuploidy and multiple stemlines was significantly associated with lymphatic metastasis (p<0.0003). Concerning distant metastasis, we found a correlation between stage IV and polyclonality. A significant correlation was observed between disease-free survival and aneuploid and polyclonal cases (p<0.0053). In polyclonal cases a nine fold greater relapse risk compared to the non-polyclonal cases was observed (p<0.0004). In two cases, the adeno-carcinoma of the sigma was polyclonal and its hepatic metastasis contained the predominant aneuploid clone with the same cytometric characteristics (DNA index) of the original lesion.

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