Objce tive To investgate the morphological monoclonal combined with SEMA 3B for detection of the tumorigenic components in gastric cancer .Methods Clones derived from gastric cancer SGC -7901 cells were assessed by morphological observation ,the clone formation rate was calculated .The expression of SEMA3B was detected by Western blot ,and the tumorigenic ability of each group was determined .Results Clones derived from GC SGC-7901 cells had three types,the total clone formation rate was(10.20 ±1.07)%,the expression of SEMA3B was the strongest in the Holoclone colonies ,SGC-7901 cells of Holoclone clones possessed strong abil-ity of self-renewal and in vivo tumorigenicity in the nude mice .Conclusion This study provides the experimen-tal basis for exploring the effect of SEMA 3B in gastric carcinoma tumor formation and proliferation .