Differential Expression of Cytokeratin 13 in Non-Neoplastic, Dysplastic and Neoplastic Oral Mucosa in a High Risk Pakistani Population

Background: Gradual loss of cytokeratin 13 (CK13) may be linked with the severity of dysplastic changesand transformation to malignancy. In this study we assessed the differential expression of CK13 in normal,hyperplastic, dysplastic and cancerous oral mucosa. Materials and
Methods: A total of 93 oral biopsies werecollected during the 2011-2014 period. The biopsies were characterized as normal (19), hyperplastic (21), severelydysplastic/carcinoma in situ (16) and invasive oral squamous cell carcinoma (OSCC) (37) after morphologicalassessment. Formalin fixed paraffin embedded sections were stained with a monoclonal antibody against CK13using the Envision technique. Immunohistochemically stained slides were then analyzed for CK13 expression.
Results: CK13 was consistently and diffusely expressed in all normal and hyperplastic tissue biopsies fromoral mucosa. Severely dysplastic/carcinoma in situ biopsies showed complete loss in 50% of cases, while in theremaining 50% expression was very focal and weak. OSCC cases showed complete or near complete loss ofCK13 in all cases. Few cases showed weak expression in keratin pearls only.
Conclusions: This study validates theutility of CK13 IHC as a useful immunohistochemical marker in routine diagnostic practice to make distinctionbetween non-neoplastic from dysplastic and neoplastic (malignant) oral lesions.