Diagnostic accuracy of pan-TRK immunohistochemistry in differentiating secretory carcinoma from acinic cell carcinoma of salivary gland-A systematic review.

BACKGROUND

Secretory carcinoma (SC) is a well-established salivary gland malignancy that has earned its popularity for its unique clinicopathological behavior. Although it is an indolent malignancy, few of them have been reported with high grade transformation making it mandatory to differentiate it from its prime histological mimicker, acinic cell carcinoma (AciCC). Recently, many studies have been directed toward validating the sensitivity and specificity of pan-TRK IHC for confirming ETV6::NTRK3 gene fusion in SCs involving salivary gland.

AIM

The aim of the present systematic review was to establish the diagnostic utility of pan-TRK immunostaining in histological differentiation of SC from AciCC.

MATERIAL AND METHODS

An electronic search was carried out using MEDLINE by PubMed, Scopus, Google scholar, Trip, Cochrane library and EMBASE databases. Articles in which SC assessed with pan-TRK immunohistochemical expressions were included for systematic review and their staining pattern (cytoplasmic, nuclear and/or combined), sensitivity, specificity, positive as well as negative predictive were gathered. Risk of bias was analyzed for each study using QUADAS-2 tool.

RESULTS

Thirteen eligible articles were included for the quantitative analysis, which revealed positive immunostaining of pan-TRK by nearly all the ETV6::NTRK3 fusion prevalent SCs alongside negative expression in almost all the cases of AciCC with 100% of sensitivity as well as specificity.

CONCLUSION

The evidence from the included studies supports that pan-TRK immunostaining could be used as a reliable preliminary screening tool for discerning SC from AciCC. PROSPERO No: CRD42022308913.