Core Insights - A key gene mutation in the human immune protein Fas ligand (FasL) may increase cancer susceptibility in humans compared to close relatives like chimpanzees, providing important clues for developing new cancer therapies [1][2] Group 1: Research Findings - The study published in Nature Communications highlights that elevated levels of plasmin, a protease, in the tumor microenvironment act like "molecular scissors" that cut mutated FasL, leading to a loss of its anti-cancer function [1] - This unique vulnerability in humans explains why immunotherapies like CAR-T are effective against blood cancers but struggle with solid tumors such as triple-negative breast cancer, as blood cancer cells do not rely on plasmin for dissemination [1] Group 2: Implications for Treatment - The mutation in FasL may have contributed to increased brain capacity in humans but also poses a risk for higher cancer susceptibility, suggesting a potential "key" to unlocking immunotherapy [2] - Blocking plasmin or protecting FasL could reactivate the immune system's anti-cancer capabilities, offering new strategies for treating challenging cancers like triple-negative breast cancer through the combined use of plasmin inhibitors and existing therapies [2]