[Nuclear DNA content in nasopharyngeal carcinoma (NPC) cells]

Cancer cell nuclear DNA content of 40 biopsy imprints of NPC was measured by Leitz MPV3 microspectrophotometer using scanning method. The pathological diagnosis and histological classification were done on the same specimens. By morphology, the poorly differentiated squamous carcinoma (34 cases) could be divided into four subtypes: ordinary nucleus type (14), spindle nucleus type (5), large and pleomorphic nucleus types (12 and 3). The first two types revealed a bimodal peak DNA histogram (2C and 4C) and slightly scattering toward the right to the 8C region in some nuclear DNA. The large nucleus type showed the bimodal peaks with a broad 4C and many nuclear DNA located in the 4C-8C range. The pleomorphic nucleus type appeared as multiple low peaks diffusing between 2C-12C. The vesicular nucleus cell carcinoma (3 cases) had a double peak DNA histogram similar to the ordinary nucleus type. The undifferentiated cell carcinoma (1 case) showed a broad unimodal peak DNA, ranging from 2C to 6C. The well differentiated squamous carcinoma (2 cases) had a double peak DNA, which was close to the normal diploid pattern but each peak was relative wide and a few DNA value located beyond the 4C region. The results indicate that DNA values showing a predominance of double peak histogram and diploid pattern imply the low grade malignancies in its biological behavior. In contrast, those showing the aneuploid and multiploid patterns in the majority of cancer cells point to the high grade malignancies. Hence, the supplementary DNA measurement of NPC cells can judge exactly the malignant degree of the tumor and provide evidence for prognosis.