As a study directly addressing TIME features in TTF-1-negative LUAD, Tanaka et al. found that Serglycin (SRGN), secreted by TTF-1-negative lines, was associated with increased tumor PD-L1 and PD-1+ T-cell infiltration [47], suggesting a more immune-inflamed yet immunosuppressed TIME. The gene discussed is TTF1; the disease is neoplasm.