Rare t(X;14)(q28;q32) translocation reveals link between MTCP1 and chronic lymphocytic leukemia

Some genes that are part of balanced translocations are reported as drivers for tumourigenesis. Here, the authors report a translocation involving MTCP1 in chronic lymphocytic leukemia and show that MTCP1 overexpression leads to the disease in a murine model. Rare, recurrent balanced translocations occur in a variety of cancers but are often not functionally interrogated. Balanced translocations with the immunoglobulin heavy chain locus (IGH; 14q32) in chronic lymphocytic leukemia (CLL) are infrequent but have led to the discovery of pathogenic genes including CCND1, BCL2, and BCL3. Following identification of a t(X;14)(q28;q32) translocation that placed the mature T cell proliferation 1 gene (MTCP1) adjacent to the immunoglobulin locus in a CLL patient, we hypothesized that this gene may have previously unrecognized importance. Indeed, here we report overexpression of human MTCP1 restricted to the B cell compartment in mice produces a clonal CD5(+)/CD19(+) leukemia recapitulating the major characteristics of human CLL and demonstrates favorable response to therapeutic intervention with ibrutinib. We reinforce the importance of genetic interrogation of rare, recurrent balanced translocations to identify cancer driving genes via the story of MTCP1 as a contributor to CLL pathogenesis.

Automated summary

Some balanced translocations can drive tumourigenesis, with MTCP1 identified as a driver gene in chronic lymphocytic leukemia. Overexpression of MTCP1 in mice leads to disease, highlighting the importance of genetic interrogation to identify cancer-driving genes. Discovery of MTCP1's role in CLL pathogenesis reinforces the need for further investigation of rare, recurrent balanced translocations.