Objective   This study aims to investigate the expression levels of CUL4A and CUL4B in limited small cell lung cancer(L-SCLC) and to explore its relationship with clinicopathologic characteristics and clinical outcomes of L-SCLC.

  Methods   The expression levels of CUL4A and CUL4B were detected immunohistochemically in 72 cases of L-SCLC tissues and 14 cases of para-cancerous tissues in tissue microarrays.

  Results   The positive rate of CUL4A was significantly higher in L-SCLC tissues(72.2%)52/72, than in para-cancerous tissues(35.7%5/14;P < 0.05).The expression level of CUL4A was closely related to smoking history(P < 0.05) but not to gender, age, primary tumor size, lymph node status, pleura invasion status, platelet(PLT) count, and lactate dehydrogenase(LDH) activity(P > 0.05).The positive rate of CUL4B was significantly higher in L-SCLC tissues(68.1%49/72) than in para-cancerous tissues(28.6%4/14;P < 0.05).The expression of CUL4B was closely related to gender and smoking history(P < 0.05) but not to age, primary tumor size, lymph node status, pleura invasion status, PLT count, and LDH activity(P > 0.05).In univariate analysis, lymph node status, CUL4A, CUL4B, and LDH were related to progression-free survival(PFS) and overall survival(OS).Multivariate analysis revealed that CUL4B independently influenced OS.However, lymph node status and LDH were independent risk factors of both PFS and OS.

  Conclusion   CUL4 may be a critical factor in L-SCLC progression.Thus, it could be a novel potential bio-marker that can predict the prognosis of L-SCLC and allow for targeted therapeutics.