The results have shown that GCMSC-CM could up-regulate c-Myc and PD-L1 expression in GC cells and the PD-L1 level decreased after JQ1, a BET domain inhibitor added, which inhibits BRD4 that acts as co-factors for Myc transcription (Fig. 3a, b). The gene discussed is BRD4; the disease is gastric cancer.