The enzyme S-methyl-5′-thioadenosine phosphorylase (MTAP) is of topical interest because its inactivation by homozygous 9p21.3 deletion occurs commonly in cancer and offers several new therapeutic and diagnostic options. Because of its pivotal position in the salvage pathway for adenine synthesis, synthetic lethality occurs in MTAP deficient cancer cells if these are exposed to drugs targeting PRMT5, MATA2, or enzymes of “de novo” adenine synthesis. Because MTAP is ubiquitously expressed, a homozygous deletion of the MTAP gene results in a complete expression loss which is detectable by IHC. In surgical pathology, a complete MTAP negativity by IHC is considered a surrogate for a homozygous 9p21 deletion and viewed as a marker for neoplastic transformation in case of cancer-suspicious mesothelial, urothelial, or other cells.

To systematically assess the prevalence of MTAP deficiency in different cancer types, and to assess the diagnostic utility of MTAP IHC, researchers from the University of Hamburg have now successfully analyzed 13’067 tumors from 149 different tumor categories for MTAP expression in formalin fixed archival tissues[1]. They used our antibody MSVA-741R which was thoroughly validated on 76 different normal tissue types by comparison with an independent second antibody and RNA expression data.

CPA1 (clone MSVA-601M) is a new marker for immunohistochemistry with very high sensitivity and specificity (>99%) for acinar cell carcinoma of the pancreas. A study on 15,680 tumors of >100 different tumor entities was recently published in the American Journal of Surgical Pathology.[1]

Acinar cell carcinoma of the pancreas makes up for only 1-2% of pancreatic tumors but is misdiagnosed in a considerable fraction of cases. Based on the data by Uhlig et al, the use of MSVA-601M results in a considerably safer distinction of this tumor entity.

The immunohistochemical visualization of CTLA-4 on formalin fixed tissues has so far been hindered by a relative lack of CTLA-4 antibodies suitable for immunohistochemistry.

In a recent study published in Laboratory Investigation by nature, researchers from the University of Hamburg have successfully analyzed 4582 tumor samples from 90 different tumor entities for quantification of CTLA-4 positive lymphocytes in formalin fixed archival tissues[2]

In their paper, Dum et al. utilized two antibodies including our newly developed clone MSVA-152R in combination with artificial intelligence to reliably count CTLA-4 positive cells. Based on these data, the antibody MSVA-152R has emerged as a highly useful tool for research on CTLA-4.