Metastatic adenocarcinoma of unknown primary site: abnormalities of cellular DNA content and survival.
Using a new flow cytometric technique we measured the cellular DNA content of tumour biopsies taken from 152 patients presenting with metastatic adenocarcinoma or undifferentiated carcinoma of unknown primary site. One hundred and six (70%) contained populations of cells with an abnormal cellular DNA content and the remainder were diploid. The incidence of aneuploidy was similar for the two sexes and bore no obvious relationship to the various patterns of metastatic involvement. Median survival of patients with diploid tumours was 4.2 months and for patients with aneuploid tumours, 4.8 months. Nine of the 46 patients with diploid tumours (i.e. 18%) survived for more than 2 yr compared to 10 of 106 (9%) of those with aneuploid tumours. These results indicate that the incidence of aneuploidy in this heterogeneous group of patients is similar to that reported for adenocarcinomas of known histogenesis, such as breast or colorectal cancer. In contrast to many of these tumour types, however, patients with metastatic adenocarcinomas of unknown primary which are diploid do not on the whole have a more favourable prognosis.