Furthermore, it has been found that in patients receiving the drug durvalumab to treat non-small cell lung carcinoma and transitional cell carcinoma had higher response rates to the drug, and the drug stunted the progression of both types of cancer for a longer duration of time. Thus, promoting the upregulation of type II IFN has been proven to be a crucial part in creating effective cancer immunotherapy treatments. IFN-γ is not approved yet for the treatment in any cancer immunotherapy. However, improved survival was observed when IFN-γ was administrated to patients with bladder carcinoma and melanoma cancers. The most promising result was achieved in patients with stage 2 and 3 of ovarian carcinoma. On the contrary, it was stressed: "Interferon-γ secreted by CD8-positive lymphocytes upregulates PD-L1 on ovarian cancer cells and promotes tumour growth." The in vitro study of IFN-γ in cancer cells is more extensive and results indicate anti-proliferative activity of IFN-γ leading to the growth inhibition or cell death, generally induced by apoptosis but sometimes by autophagy. In addition, it has been reported that mammalian glycosylation of recombinant human IFN-γ, expressed in HEK293, improves its therapeutic efficacy compared to the unglycosylated form that is expressed in E. coli. Involvement in antitumor immunity Type II IFN enhances Th1 cell, cytotoxic T cell, and APC activities, which results in an enhanced immune response against the malignant tumor cells, leading to tumor cell apoptosis and necroptosis (cell death). Furthermore, Type II IFN suppresses the activity of regulatory T cells, which are responsible for silencing immune responses against pathogens, preventing the deactivation of the immune cells involved in the killing of the tumor cells. Type II IFN prevents tumor cell division by directly acting on the tumor cells, which results in increased expression of proteins that inhibit the tumor cells from continuing through the cell cycle (i.e., cell cycle arrest). Type II IFN can also prevent tumor growth by indirectly acting on endothelial cells lining the blood vessels close to the site of the tumor, cutting off blood flow to the tumor cells and thus the supply of necessary resources for tumor cell survival and proliferation. Barriers The importance of type II IFN in cancer immunotherapy has been acknowledged; current research is studying the effects of type II IFN on cancer, both as a solo form of treatment and as a form of treatment to be administered alongside other anticancer drugs. But