Objective: The objective was to investigate the expression of HPV16 L1 capsid protein in cervical neoplasia to analyse its association with different grades of cervical lesions and its implication as a prognostic marker.

Materials and Methods: Detection of L1 capsid protein of HPV16 by immunostaining was done using anti-HPV16 mouse monoclonal antibody against L1 fusion protein in cervical scraping or biopsy specimens obtained from subjects (n=79) after confirmation of cytological/histological diagnosis.

Results: Total 79 cases of cervical cancerous lesions in a graded spectrum were observed for expression of L1 capsid protein of HPV16, among which 30 cases showed L1 expression and 49 cases did not. The expression rates of L1 protein among ASCUS, ASC-H, LSIL and HSIL were 37.50%, 66.67%, 80% and 44.44% respectively. Among invasive lesions, the L1 expression rates were 25%, 15.38% and 8.33% in well, moderately and poorly differentiated SCC respectively. Overall the L1 positivity rate was 37.97%. The expression of L1 proteins decreased with increase in lesion grade. This declining trend of L1 positivity rate with increasing grade of lesion was extremely significant (p value for chi squared for trend is 0.0005). The difference of L1 expression between preinvasive and invasive group was also significant (p<0.0001).

Conclusion: Expression of L1 capsid protein of HPV16 was high in lower grade preinvasive lesions and it steadily declined with increasing grade of lesion. HPV16 L1 Protein expression can be used as a prognostic tool and a marker of immune response against HPV16.

Keywords: Human Papilloma Virus 16, L1 capsid protein, cervical neoplasia, Immunohistochemistry.

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Rajat Kanti Biswas

Associate Professor, Department of Pharmacology, Malda Medical College, Malda, India