Xeroderma pigmentosum variant: DNA ploidy analysis of various skin tumors and normal-appearing skin in a patient.

BACKGROUND

The patient with xeroderma pigmentosum provides an appropriate human model for the evaluation of tumor development and progression.

METHODS

We describe a patient with variant-type xeroderma pigmentosum who developed actinic keratoses, a squamous cell carcinoma, and its metastasis into a lymph node. DNA ploidy was measured and analyzed in cells of these tumors and the patient's sun-exposed as well as sun-shielded skin.

RESULTS

The sun-shielded skin showed a normal diploid DNA distribution pattern, while the sun-exposed skin had an increased number of hyperdiploid cells. The actinic keratosis showed further increased hyperdiploid cells. The squamous cell carcinoma showed a large number of hyperdiploid cells and formed an aneuploid cell fraction. Histographically, the aneuploid cell fraction became more apparent and was revealed to be a major fraction in the metastatic squamous cell carcinoma.

CONCLUSIONS

The changes in the DNA ploidy pattern well reflect the clinical and histologic characteristics of the respective skin conditions and likely provide the cellular basis for the sequential or stepwise carcinogenic process in the patient's xeroderma pigmentosum skin. Further studies are necessary to determine whether the present results explain the similar carcinogenic process in sun-damaged skin of the nonpredisposed general population.