Expression of CK-19 in Papillary Thyroid Carcinoma and Its Association with Prognostic Factors - A Cross-Sectional Study

BACKGROUND Papillary thyroid carcinomas (PTC) are the most common carcinomas of the thyroid. Diagnosis of PTC is with its distinct nuclear features. Prognosis of PTC is favourable but can also be aggressive as demonstrated by its recurrence. So, we wanted to improve the present diagnostic tools to identify cases with aggressive course. Immunohistochemistry (IHC) markers which are thought to be useful are CK-19 and CD56. METHODS This is a cross sectional study, done in the Department of Pathology, Government Medical College, Thiruvananthapuram from January 2018 to May 2019. Histopathology slides were prepared from 80 samples, IHCs performed, and the data was analysed using statistical software SPSS version 23.0. RESULTS The classic variant was the most common. In the study, predominant population was below 45 years. There was a female predominance and majority of cases had a tumour size of more than 1 cm. 23.8 % of the cases showed lymph node metastasis. On evaluating CK-19 expression in PTC, 98.75 % showed a positive expression, but there was no association between CK-19 expression and factors like age, gender, tumour size, and lymph node metastasis. 96.3 % of cases showed a loss of expression of CD56. CONCLUSIONS Both CK-19 and CD56 can be used together as markers for PTC including all their variants but CK-19 cannot be used to assess the prognosis of PTC as no association was identified in the study between the expression of CK-19 and prognostic factors.