Role of P40 immunohistochemistry in diagnosing primary cervical squamous cell carcinoma in comparison to P63

Cervical cancer is one of the most common gynaecological tumours, with squamous cell carcinoma is the commonest histological subtype. Human papillomavirus (HPV) is an established primary cause of cervical carcinoma. p63 is proven to be of diagnostic value in cervical squamous cell carcinoma. p40 is a p63 isoform that causes p53 inactivation and is positively expressed in squamous cell carcinoma. However, there are limited data on p40 expression in cervical squamous cell carcinoma. This study aims to determine the role of p40 in diagnosing primary cervical squamous cell carcinoma and to evaluate the specificity and sensitivity of p40 in cervical squamous cell carcinoma in comparison to p63. A retrospective study was conducted in Pusat Perubatan Universiti Teknologi MARA (UiTM) Sungai Buloh, Malaysia where a total of 83 cases diagnosed as primary cervical carcinoma from January 2013 to December 2019 were reviewed and stratified into different histological subtypes. These cases were subjected to p40 and p63 immunohistochemistry staining. The data were analysed to evaluate p40 and p63 expression in cervical carcinoma, and the results of tumour immunoreactivity for both markers were compared. The results showed that p40 was strongly expressed in most cervical squamous cell carcinoma and adenosquamous carcinoma. p63 expression was also positive in cervical squamous cell carcinoma; however, variable reactivity was seen in other histological subtypes. The results also suggested that p40 is more specific but slightly less sensitive in identifying squamous differentiation than p63. These findings support the use of p40 immunohistochemistry as a potential reliable marker in diagnosing primary cervical squamous cell carcinoma.