Hyperdiploidy of cultured dermal fibroblasts from patients with aerodigestive squamous carcinoma

The incidence of hyperdiploidy in monolayer cultures of dermal fibroblasts from 88 patients with squamous carcinoma of the aerodigestive tract was compared with similar cultures from 39 normal subjects using three different techniques; 1) metaphase assay (MA), 2) flow cytometry of stationary cell cultures (FCMs), and 3) flow cytometry of proliferating dividing cell cultures (FCMd). In vitro hyperdiploidy was considered to be present (IVH+): 1) by MA if more than 4% of metaphases were altered, excluding tetraploidy; 2) by FCMs if more than 8% of cells in stationary cultures were hyperdiploid (i.e., DNA index greater than 1), and 3) by FCMd if more than 6% of cells in logarithmic cultures were hypertetraploid (i.e., DNA index greater than 2). There was excellent concordance between the three assays, which assigned cell cultures from 55 of the 88 patients with aerodigestive squamous carcinoma (62%) to the in vitro hyperdiploidy positive (IVH+) category. Cell cultures from all 39 normal individuals were hyperdiploidy negative (IVH-). These data suggest that some substantial proportion of patients with aerodigestive squamous carcinoma may have a genetic predisposition for the disease, which can be identified by these assays. The flow cytometry methods were easier to carry out and may be substituted for the metaphase analyses.