肿瘤精准免疫治疗的临床实践

Clinical practice of cancer precision immunotherapy

目的通过二代高通量测序,评估肿瘤组织的潜在驱动突变和人类白细胞抗原(HLA)I类基因突变,预测肿瘤患者对主要组织相容性复合物I类分子(MHC-I)限制性的免疫治疗手段,如程序性死亡受体1(PD-1)单抗或多靶点抗原肽自体免疫细胞治疗技术(MASCT)的有效性。方法对35例肿瘤组织样本进行333个肿瘤相关基因二代高通量测序,根据肿瘤组织样本中基因突变信息将35例肿瘤样本进行Dirichlet Multinomial Mixture(DMM)分类分析,并根据肿瘤组织HLA-I类基因突变量,结合对患者肿瘤组织中检测到的点基因突变位点,分析预测能引起免疫响应的新生抗原肽数目,预测患者对MHC-I类分子限制性免疫治疗——PD-1单抗或MASCT单用或联用治疗中的临床疗效,并根据实际治疗结果对预测方法进行优化和改进。结果 35例肿瘤组织样本根据肿瘤相关基因测序和DMM分类分析,形成2个分组。DMM 2个分组中,HLA-I类基因突变量差异显著(P=1.076e-5)。其中5例患者接受免疫治疗,对结果进行个案分析:2例HLA-I类基因高突变量患者进行MHC-I类分子限制性免疫治疗PD-1单抗联用MASCT,或单用MASCT治疗3次或3次以上,患者临床评估为疾病进展;3例HLA-I类基因低突变量患者,进行PD-1单抗单用或联用MASCT 4次以上,2例患者临床评估为疾病控制,1例患者临床评估为疾病稳定。结论通过特定的基因测序,检测患者肿瘤组织驱动突变和HLA-I类基因突变量,对患者进行分类,筛选适合MHC-I类分子限制性肿瘤免疫治疗适应证人群,提高临床肿瘤免疫治疗有效率,达到精准免疫治疗的目的。

Objective To predict the response rate and effectiveness of major histocompatibility complex（MHC） class I restricted immunotherapy such as PD-1 inhibitor or multiple antigen specific cancer therapy（MASCT） through evaluating the cancer cell driver mutations and human leukocyte antigen（HLA） class I gene mutations loading using the next generation sequencing（NGS）. Methods Through the next generation sequencing for 333 cancer associated genes and using Dirichlet Multinomial Mixture package in RStudio software for classification, 35 cancer samples were clustered into two subgroups. HLA-I genes mutation loading was evaluated for each sample and the neoantigens generated by non-synonymous point mutations were predicted, and then the 35 cancer patients were predicted as for their response for MHC-I restricted immunotherapy. Results Five patients among the 35 NGS sequenced samples were predicted as for their response after receiving PD-1 inhibitor and MASCT monotherapy or combination therapy. Two patients with higher HLA-I gene mutation loading that were predicted as non-responders received PD-1 inhibitor（Keytruda） and MASCT combined therapy or MASCT monotherapy for over three times. The two patients were clinically evaluated as progressive disease（PD）; Other three patients with relative lower HLA-I gene mutation loading and higher neoantigens that were predicted as responders, received PD-1 inhibitor（Keytruda） and MASCT combined therapy or MASCT monotherapy for over four times, with two patients being clinically evaluated as partial response（PR） and one patient evaluated as stable disease（SD）. Conclusion Through NGS for cancer associated genes mutations, the response for MHC-I restricted immunotherapy may be predicted and cancer immunotherapy efficiency may be improved.