摘要标题：中国妇科肿瘤患者的分子谱及肿瘤突变负荷分析

Background: Gynecologic cancers account for approximately 18% of all female cancers. Since management options for advanced gynecologic cancers are limited, immune checkpoint blockade is a potential therapy to be investigated in several clinical trials. Despite being an emerging biomarker of sensitivity to immune checkpoint inhibitors, the tumor mutational burden (TMB) in Chinese patients with gynecologic cancer has not been well characterized yet. 

研究背景：妇科肿瘤约占所有女性癌症的18%。由于晚期妇科肿瘤的治疗手段有限，一些研究者在临床试验中发现，，免疫检查点抑制剂疗法是一种潜在的治疗方法。虽然肿瘤突变负荷(TMB) 是免疫检测点抑制剂敏感性的新兴生物标志物，但是在中国妇科肿瘤患者尚未得到很好的描述。

Methods: In total, 117 patients with gynecologic cancers were included in this study. Both tumor DNA and paired blood cell genomic DNA were isolated from formalin-fixed paraffin-embedded (FFPE) specimens and blood samples and subjected to enrichment for a 1.15 Mb-panel representing exonic regions from 1086 genes, followed by next-generation sequencing on an Illumina X10 platform. The captured sequencing data were further subjected to bioinformatics analysis to identify somatic mutations, including single nucleotide variants (SNVs) and short insertions/deletions (indels). In addition, TMB values were evaluated and analyzed. 

研究方法：本研究共纳入了117例妇科肿瘤患者。每位患者都有配对样本，从甲醛固定的石蜡标本中提取肿瘤DNA，从配对的血液样本中提取血细胞基因组DNA。对特定的1086个基因的1.15 MB外显子区域进行富集，通过Illumina X10平台上进行高通量测序（NGS）。对捕获的测序数据进行生物信息学分析，主要分析体细胞突变，包括单核苷酸变异(SNVs)和短插入/缺失(indels)等变异。此外，还对TMB值进行了评估和分析。

Results: TP53, PTEN, ARID1A, and PIK3CA alterations were significantly different in various types of gynecologic cancers (p=0.001, 1.15E-07, 0.004, and 0.009, respectively). The median TMB of all 117 gynecologic tumor specimens was 0.37 mutations/Mb, with a range of 0-41.45 mutations/Mb. Despite the lack of significant difference, endometrial cancer cases had a higher median TMB than did cervical and ovarian cancer cases (p=0.81). Younger gynecologic cancer patients (age<40 years) had a significantly lower TMB than did older patients (age≥40 years) (p=0.04). In addition, TMB was significantly increased with increasing clinical stage of disease (p=0.001). PTEN alterations were commonly observed in patients with a moderate to high TMB (n=8, 38.10%, p=9.95E-04). Although limited by sample size, all of the patients with TSC2 (n=3, p=3.83E-11) or POLE (n=2, p=0.005) mutations had a moderate to high TMB. 

研究结果：不同类型妇科肿瘤中的TP53、PTEN、ARID1A和PIK3CA基因变异均有显著差异(分别为P=0.001, P=1.15 -07, P=0.004, P=0.009)。117例妇科肿瘤标本的中位TMB为0.37突变/Mb，范围为0-41.45突变/Mb。结果表明：子宫内膜癌患者的TMB中值高于宫颈癌和卵巢癌(虽然数据没有显著性差异，p=0.81)。年轻的妇科肿瘤患者(年龄< 40岁)TMB显著低于老年患者(年龄≥40岁)(p = 0.04)。此外，TMB随着疾病临床分期的增加而显著增加(p=0.001)。携带PTEN突变的患者，TMB值在TMB-M到TMB-H范围内 (n=8, 38.10%， p=9.95 -04)。虽然样本量有限，但所携带TSC2突变 (n=3, p=3.83E-11)或POLE(n=2, p=0.005)突变的患者，其TMB值均在TMB-M到TMB-H范围内。

Conclusions: Patients with mutations in the PTEN, TSC2 or POLE gene have increased TMB. However, further large-scale, prospective studies are needed to validate our findings.

研究结论：携带PTEN、TSC2或POLE突变的患者，TMB值更高。然而，还需要进一步的大规模的前瞻性研究来验证我们的发现。