IFNG and neoplasm: Finally, we determined that the frequency of CTLs, mRNA levels of Granzyme B and IFN-γ in the tumor (Fig. 5h), and results showed L-Arg treatment significantly enhanced frequency and CTLs, and mRNA level of Granzyme B (a 10-fold increase compared with PBS) and IFN-γ (4-fold compared with PBS) significantly elevated.