T cells engineered to target MSLN (TCR1045) can preferentially accumulate within established tumors on adoptive transfer, delay tumor growth, and significantly prolong survival in the ID8VEGF murine ovarian cancer model of established, disseminated disease.10 However, the previous study also revealed that elements in the tumor microenvironment (TME) limit engineered T cell persistence and the ability to eradicate cancer cells. This evidence concerns the gene MSLN and neoplasm.