Cell cycle arrest and programmed cell death are crucial biological processes in cancer development. Regulating cell fate decisions is essential due to their potential to induce cell cycle arrest and cell death. Inducing cell cycle regulatory proteins in tumor cells is considered a key objective in cancer therapy. Here, we present a novel method that selects antibodies from an antibody library to inhibit cancer growth using fluorescence-activated cell sorting (FACS) assays and cell cycle analysis. This approach seeks antibodies that induce cancer cells to enter the G0 or G1 phase, a quiescent state where cells cease to proliferate and trigger programmed cell death. We found that the T1 antibody effectively suppresses the proliferation of cancer cells. Mechanistically, serine protease 3 (PRSS3) is a target antigen of the T1 antibody. We demonstrated that PRSS3 controls tumor cell proliferation and apoptosis through interaction with the T1 antibody. This research suggests that PRSS3 holds great potential as a target for solid cancer treatment. This cycle-based approach to antibody screening shows potential because it can be broadly applied to cancer and other challenging diseases.