Sun H, Liu L, Huang Q, et al. - Researchers sought clarity regarding the role of CD49a⁺ natural killer (NK) cells in the development of liver diseases. Compared with peritumoral tissues, human hepatocellular carcinoma (HCC) exhibited a higher accumulation of CD49a⁺ tissue-resident NK cells. Via protein and mRNA analysis, they examined the exhausted and regulatory phenotypes of CD49a⁺ tissue-resident NK cells. They found a positive correlation between the proportion of CD49a⁺ NK cells and the proportion of NK cells showing inhibitory receptors. When murine and human CD49a⁺ NK cells were compared, distinct features and functions were revealed. Findings also revealed a correlation between accumulation of tissue-resident CD49a⁺ NK cells in liver tumor and deteriorating disease condition and poor prognosis. In this study, the accumulation of CD49a⁺ NK cells in liver tumor was shown and a role for CD49a⁺ NK cells in the negative regulation of immune responses and HCC development was suggested.