MSLN and breast cancer: Given the exceptional immune‐stimulatory activity and anticancer effect of STYMIE #30, we further assessed its treatment efficacy against a 4T1 breast cancer model[49] and a Lewis lung carcinoma (LLC) model[50] Mesothelin‐expressing 4T1 and LLC cell lines (mesothelin‐4T1 and mesothelin‐LLC) were first established and injected subcutaneously into BALB/c mice and C57BL/6 mice, respectively.