p53 immunostaining and image cytometry DNA analysis in precancerous and cancerous squamous epithelial lesions of the larynx.

BACKGROUND: Squamous epithelial cancer can develop from progressive epithelial changes connoted dysplasias. Histopathologic evaluation/grading of these lesions is difficult and gives poor information concerning the risk for progression to cancer. Squamous cell carcinoma of the head and neck (SCCHN) frequently show p53 alteration and DNA-ploidy aberration. Could these markers be used as indicators for malignancy risk in the larynx?

METHODS: Immunohistochemical staining (IHC), with the CM-1 antibody against p53, and image cytometry (ICM) DNA analysis were performed in 60 lesions from 12 patients--and 21 controls--who were initially seen with laryngeal lesions prior to cancer in situ (cis) or invasive cancer diagnosis at the same site.

RESULTS: All but one of the invasive cancers, and 77% of the lesions which preceded cancer or cancer in situ, showed positive p53 immunostaining, as compared with only 10% of the controls. All but one of the invasive cancer lesions, and 77% of the precancerous lesions, showed aberrant DNA-ploidy results, whereas all controls were diploid. When DNA and p53 analysis were combined, only one of the lesions preceding cis or invasive cancer was negative.

CONCLUSIONS: Both p53 immunoreactivity and DNA-ploidy aberration appear to be early events in the multistep process of squamous epithelial carcinogenesis. Immunohistochemical staining p53 analysis and ICM DNA analysis does increase the diagnostic sensitivity for cancerous and true precancerous lesions in the larynx.