Wu SY, Liao P, Yan LY, et al. - In various malignancies, especially in hepatocellular liver carcinoma (LIHC), MKI67 (marker of proliferation Ki-67) behaves as a prognostic prediction biomarker.

• Multiple databases were used to assess the role of MKI67 as prognosis predictor as well as its links with T cell activity and immune infiltration within various cancers, especially LIHC.

• MKI67 expression reduced in several cancers associated with the dismal prognostic outcome of LIHC.

• LIHC prognosis, in terms of histology and grade, is significantly impacted by MKI67.

• An increase in the degree of immune infiltration of many immune cell subtypes, including functional T cells, CD4+ T cells, and CD8+ T cells, was observed due to MKI67 upregulation.

• A close correlation between MKI67 and T cell exhaustion was found, which has an important role in promoting T cell exhaustion within LIHC.

• MKI67 level detection contributes to prognosis prediction as well as MKI67 modulation within exhausted T cells, hence affording a new tool to optimize anti-LIHC immunotherapy efficacy.