Progression of hepatocellular carcinoma as reflected by nuclear DNA ploidy and cellular differentiation

Intratumor heterogeneity of DNA ploidy within a single hepatocellular carcinoma is not well understood. The present study was designed to examine the histologic distribution of intratumor DNA ploidy in hepatocellular carcinomas of different growth types in relation to cell differentiation.

Twenty patients (16 men and four women; mean age, 60.2 years) with hepatocellular carcinoma (mean diameter, 4.3 cm) were studied. One hundred and twenty-seven samples from different sites of each tumor were analyzed by determination of the nuclear DNA content and histological examination.

The DNA ploidy was heterogeneous in nine (45%) of the 20 tumors. Five tumors had a mixture of diploid and aneuploid regions, and the remaining four consisted of aneuploid regions with different DNA indices. There was no significant difference in patient characteristics between the heterogeneous and homogeneous groups. A significant correlation was found between tumor growth type and the incidence of heterogeneity. Only 16% of single nodular carcinomas without intratumor septal formation exhibited heterogeneity, while single nodular tumors with septal formation or confluent multinodular tumors were associated with high incidences of different DNA ploidy patterns or DNA indices. There was no aneuploidy in well-differentiated foci, while aneuploidy was frequently found in moderately or poorly differentiated foci (incidences of 67% and 74%, respectively).

Heterogeneity of DNA ploidy may develop along with changes in growth pattern and cell dedifferentiation or by confluence of nodules originating from different tumor cell clones.