FLOW CYTOMETRIC DNA CONTENT-ANALYSIS ON SQUAMOUS-CELL CARCINOMAS ACCORDING TO THE PRECEDING LESIONS

DNA-ploidy in primary cutaneous squamous cell carcinomas which had dev eloped from different preceding clinical lesions was examined by flow cytometry using paraffin-embedded blocks. DNA-aneuploidy was detected in none of 15 squamous cell carcinomas arising from a burn scar. On th e other hand, 12 of 26 squamous cell carcinomas arising from sun-damag ed skin in the elderly, and two of four arising from chronic radioderm atitis, showed aneuploid patterns. A significantly higher incidence of DNA-aneuploidy was observed in squamous cell carcinomas arising from sun-damaged skin than those from a burn scar (P < 0.01); the mean diam eter size of the former was significantly smaller than that of the lat ter (P < 0.0001). The mean age of patients with aneuploid tumours (74. 2 +/- 9.2: years +/- standard deviation (SD)) was significantly higher than that with diploid tumours (64.1 +/- 13.8) (P < 0.01).