PVT1 and Carcinoma, Lewis Lung: Surprisingly, a long noncoding RNA, Pvt1, was shown to regulate the immunosuppressive activity of PMN-MDSCs in the tumor microenvironment, and siRNA-mediated silencing of Pvt1 inhibited intratumoral PMN-MDSC activity in the Lewis lung carcinoma mouse model66 [Figure 1D(1)].