Abstract:

Objective: The purpose of this study was to evaluate the diagnostic utility of SATB2 in detecting CRC origin for patients presenting with metastatic carcinomas. Study Design: Cross sectional, comparative study. Place and Duration of Study: Study was conducted at department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi from January 2019 to June 2019. Materials and Methods: Already diagnosed 68 cases of metastatic carcinoma of various origins with unknown primary were retrieved from tumour registry. Paraffin embedded blocks were taken and a panel of Immunohistochemistry was applied which includes CK7, CK20,CDX2 and SATB2. Positivity of SATB2 alone, and  combination of SATB2 with CK 7,CK20 and CDX2 was evaluated. Results: Out of 68 metastatic adenocarcinoma cases 28(41%) had positive SATB2 expression and 38 (56%) were negative. All the positive SATB2 cases had 100 % (28/28) expression with CDX2, 93% (26/28) of the cases had expression with CK20 and 21% (6/28) of the cases showed expression of CK7. The sensitivity of SATB2 alone was 100% in metastatic colorectal carcinoma as compared to CK20 and CDX2. The sensitivity of SATB2 in combination with CDX2 (100%) and CK20 (93%)in comparison to the double combination of CK20 and CDX2(93 %). The sensitivity of SATB2 and CK20 combination was 93%, which was equal to CK20 and CDX2 combination. Conclusions: Our results show that SATB2 is a sensitive marker in the IHC panel for cases with suspected metastasis from colorectal region.

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