The Diagnostic Significance of Cytokeratin 13 & 17 Expression in Oral Mucosal Biopsies by Immunohistochemical Technique

Abstract

Objectives: To evaluate the immunohistochemical profile of Cytokeratin 13 (CK13) and Cytokeratin 17 (CK17) expression in oral premalignant and malignant epithelial lesions.

Methods: This descriptive, institution-based study was conducted at the Pathology Department, Liaquat University of Medical and Health Sciences, Jamshoro, from January 2017 to June 2017. All patients of either sex and any age group who presented with oral mucosal epithelial lesions (e.g., white lesions, ulcers, erythroplakia) and underwent excisional biopsy were included. The biopsied specimens were fixed in 10% formalin, processed using standard techniques, and stained with Hematoxylin and Eosin (H&E) for initial histopathological diagnosis.

For immunohistochemistry, serial sections (3–4 µm) were obtained from paraffin-embedded tissue blocks. CK13 and CK17 antibodies were applied to 4-?m-thick tissue microarray (TMA) sections. After deparaffinization and rehydration, endogenous peroxidase activity was blocked for 30 minutes using methanol containing 0.3% hydrogen peroxide. Care was taken to prevent tissue desiccation during staining. FLEX IHC microscope slides (Code K8020) were used to enhance tissue adherence. Clinical data and case-specific details were recorded using a pre-designed proforma. Data analysis was performed using SPSS version 20.

Results: A total of 139 cases were included. The mean age of patients was 40.45 ± 11.94 years. Males constituted the majority (63.4%). The most common biopsy sites were buccal mucosa (32.8%), cheek (21.6%), and tongue (31.3%). Most patients (78.4%) reported symptoms for 1 to 3 months. Leukoplakia was the most frequent oral lesion, observed in 22.3% of cases.

CK13 positivity was observed in 73 cases, while CK17 was positive in 96 cases. CK13 expression was significantly associated with leukoplakia, submucous fibrosis, and ulcers (p = 0.003). CK17 expression showed significant association with leukoplakia and squamous cell carcinoma (SCC) (p = 0.001). Histologically, dysplasia was significantly associated with positive CK13 expression, whereas SCC was significantly associated with CK17 expression, both with statistically significant p-values.

Conclusion: CK13 is a useful immunohistochemical marker for epithelial dysplasia, while CK17 serves as a reliable diagnostic marker for squamous cell carcinoma. CK13 expression was significantly higher in cases of leukoplakia, submucous fibrosis, ulcers, and epithelial dysplasia. CK17 was more frequently expressed in cases of leukoplakia and SCC.