PRAME is a tumor-associated antigen that is preferentially expressed on the nuclei of neoplastic melanocytes. In normal tissue, expression of this cancer testis antigen is largely restricted to testis.

Anti-PRAME can be used for differential diagnosis of melanoma with diffuse positive nuclear staining versus nevi which are negative or only focally positive for PRAME. Therefore, it can be a helpful additional examination for situations in which antibodies against Hmb-45, Melan A and SOX10 do not provide sufficient information to distinguish between benign and malignant melanocytic lesions. 

Clear cell sarcoma is reported to give consistently negative staining in contrast to malignant melanomas, and can therefore be used for differential diagnosis between clear cell sarcoma (negative) vs. malignant melanoma (positive). Most synovial sarcomas and myxoid liposarcomas are diffusely positive for PRAME.
Literature using other clones documented that PRAME is expressed not only by melanoma but also by various non-melanoma neoplasms including non-small cell lung cancer (NSCLC), breast carcinoma, renal carcinoma, ovarian carcinoma, and leukemia.

Programmed Death Ligand 1 (PD-L1), also known as CD274 and B7-H1, is a transmembrane protein expressed on the surface of resting T-cells.

Binding to its receptor PD-1, a T-cell immune checkpoint, T-cell activation is inhibited and autoimmune reaction is stopped. Some tumor cells use this mechanism to prevent apoptosis and obtain resistance against CD8+ T-cell mediated cell lysis. Blockade of the PD-1/PD-L1 pathway has now shown useful in therapy of multiple cancer types, causing durable tumor regressions in a substantial proportion of otherwise treatment refractory cases of melanoma, and carcinomas of e.g., lung, kidney, and urinary tract.

Anti-PD-L1 is suitable to detect non-small cell lung cancer (NSCLC), gastric carcinoma or melanoma. According to literature PD-L1 is known to be expressed in 36-72% of NSCLC, 33-83% of melanoma and 15-69% of gastric cancer.

TRPS1 (Transcriptional Repressor GATA Binding 1) is a nuclear transcription factor protein that mainly acts as a transcriptional repressor. It plays a critical role in the development of cartilage, bone and hair follicle. TRPS1 is highly expressed in breast epithelial tissues functioning as an essential regulator for the growth and differentiation of normal mammary epithelial cells.

TRPS1 is involved in the development of breast cancer and is required for breast cancer cell survival. Positive expression is found in >90% of breast cancer cases. Therefore, anti-TRPS1 is increasingly used in IHC to determine breast cancer subtype and evaluate tumor biology.

INSM1, also known as Insulinoma-Associated Protein 1, is a zinc finger transcription factor that plays a crucial role in neuroendocrine differentiation. Expression is found in neuroendocrine cells throughout the body.

INSM1 is found in the majority of neuroendocrine neoplasms and is used as nuclear marker of neuroendocrine differentiation. INSM1 is expressed in a broad spectrum of neuroendocrine tumors (including small cell carcinoma, large cell neuroendocrine carcinoma and well differentiated neuroendocrine tumor/carcinoid tumor of various sites).

Anti-INSM1 can be used for differentiation of pancreatic neuroendocrine tumors (100%) from pancreatic adenocarcinoma (0%). In lung, INSM1 is found in 95% of small cell carcinoma, in 91% of large cell neuroendocrine carcinoma and in about 3% of adenocarcinoma.