Recent evidence has shown that human papillomavirus (HPV) is involved in both the development of
carcinoma and in premalignant mucosal lesions of the oral cavity. This study examined the relationship of
HPV infection to some pathological features in precancerous lesions of the larynx, not examined extensively so far. Fifty
formalin-fixed
paraffin-embedded tissue sections containing human laryngeal precancerous lesions were screened for the presence of
HPV infection by polymerase chain reaction, and for
capsid protein expression by immunohistochemistry with polyclonal antibody directed against the L1
protein. The presence of HPV
DNA was detected in 28 of 50 specimens (56%), including 9/12 cases with mild dysplasia (75%), 3/6 cases with moderate dysplasia (50%), and 7/11 cases with severe dysplasia (64%). Multiple
HPV infections, containing two or three types, were detected in 17 of the 28 HPV-positive lesions (60%). Of 21 cases with
keratosis and no dysplasia, 11 were positive for HPV
DNA (52%) and 4 showed L1 staining (36%). By contrast, L1 positivity was revealed only in two lesions with moderate dysplasia, confirming that fully productive
HPV infection is strictly dependent on epithelial differentiation and surface keratinization. The probability that HPV is a cofactor in the malignant progression of these lesions is suggested by the fact that 3/4 patients who developed
cancer within 50 months were positive for HPV
DNA.