Transient overexpression of PTPRK in EBV-positive KM-H2 cells significantly decreases their growth and survival. (A) Semiquantitative RT-PCR for PTPRK mRNA (top) and immunoblotting for PTPRK (bottom) following overexpression of PTPRK in EBV-positive KM-H2 cells. (B) Cell viability (trypan blue; left) and cell proliferation (WST-1; right) assays on KM-H2-EBV cells following PTPRK overexpression. The transient expression of PTPRK in these cells results in a significant decrease in cell viability and cell proliferation at both 24 and 48 hours (* denotes significant difference; P values are .003 at 24 hours and .001 at 48 hours for viability and P values are less than .001 at both 24 and 48 hours for cell proliferation).