引言：在过去几十年中，不同的软组织肿瘤中发现了越来越多的染色体易位，这不仅对临床诊断有价值，还暗示了软组织肉瘤的发病机制。融合基因可以通过FISH、RT-PCR和下一代测序来检测。一步法RT-PCR是一种便捷的方法，可以以更高的灵敏度和更低的成本检测融合基因。方法：本研究纳入了242例软组织肿瘤，经一步法RT-PCR在七种肿瘤的多个中心进行检测：横纹肌肉瘤（RMS）、周围原始神经外胚层肿瘤（pPNET）、滑膜肉瘤（SS）、黏液型脂肪肉瘤（MLPS）、泡状软部肉瘤（ASPS）、皮肤纤维肉瘤（DFSP）和软组织血管纤维瘤（AFST）。其中，通过一步法RT-PCR检测到的18例样本进一步进行FISH检测。通过RNA测序检测到的一例新的融合基因经一步法RT-PCR进行验证。结果：通过一步法RT-PCR检测的242个样本中，融合基因的总阳性率为60％（133/213），其中由于RNA质量差无法评估的样本有29个。在滑膜肉瘤中，PAX3-FOXO1的阳性率为88.6％（31/35），pPNET中的EWSR1-FLI1的阳性率为63％（17/27），SS中的SYT-SSX的阳性率为95.4％（62/65），ASPS中的ASPSCR1-TFE3的阳性率为100％（10/10），MLPS中的FUS-DDIT3的阳性率为80％（4/5），DFSP中的COL1A1-PDGFB的阳性率为66.7％（8/12）。在213例中，与年龄和部位相关联。PAX3-FOXO1融合基因状态与横纹肌肉瘤中的淋巴结转移和远处转移相关。此外，与阴性融合基因相比，携带阳性PAX3-FOXO1融合基因的横纹肌肉瘤患者的总体生存时间显着较短。其中，18例FISH结果与一步法RT-PCR一致。有一例AFST中最常见的AHRR-NCOA2融合类型通过一步法RT-PCR检测为阴性。利用RNA测序确定了融合基因，并发现了一种新的PTCH1-PLAG1融合基因。此外，该融合基因经一步法RT-PCR确认。结论：我们的研究表明，一步法RT-PCR是检测融合基因的可靠工具，具有高准确性和低成本的优势。此外，它是识别新的融合基因的重要工具。总体而言，它为分子病理诊断提供了有用的信息，并提高了软组织肉瘤的诊断率。版权所有©2023 Song，Zhang，Wang，Xia，Guo，Cao，Xin，Cheng，Liu，Jia和Li。

Introduction: Over the past decades, an increasing number of chromosomal translocations have been found in different STSs, which not only has value for clinical diagnosis but also suggests the pathogenesis of STS. Fusion genes can be detected by FISH, RT-PCR, and next-generation sequencing. One-step RT-PCR is a convenient method to detect fusion genes with higher sensitivity and lower cost. Method: In this study, 242 cases of soft tissue tumors were included, which were detected by one-step RT-PCR in multicenter with seven types of tumors: rhabdomyosarcoma (RMS), peripheral primitive neuroectodermal tumor (pPNET), synovial sarcoma (SS), myxoid liposarcomas (MLPS), alveolar soft part sarcoma (ASPS), dermatofibrosarcoma protuberans (DFSP), and soft tissue angiofibroma (AFST). 18 cases detected by one-step RT-PCR were further tested by FISH. One case with novel fusion gene detected by RNA-sequencing was further validated by one-step RT-PCR. Results: The total positive rate of fusion genes was 60% (133/213) in the 242 samples detected by one-step RT-PCR, in which 29 samples could not be evaluated because of poor RNA quality. The positive rate of PAX3-FOXO1 was 88.6% (31/35) in alveolar rhabdomyosarcoma, EWSR1-FLI1 was 63% (17/27) in pPNET, SYT-SSX was 95.4% in SS (62/65), ASPSCR1-TFE3 was 100% in ASPS (10/10), FUS-DDIT3 was 80% in MLPS (4/5), and COL1A1-PDGFB was 66.7% in DFSP (8/12). For clinicopathological parameters, fusion gene status was correlated with age and location in 213 cases. The PAX3-FOXO1 fusion gene status was correlated with lymph node metastasis and distant metastasis in RMS. Furthermore, RMS patients with positive PAX3-FOXO1 fusion gene had a significantly shorter overall survival time than those patients with the negative fusion gene. Among them, the FISH result of 18 cases was concordant with one-step RT-PCR. As detected as the most common fusion types of AHRR-NCOA2 in one case of AFST were detected as negative by one-step RT-PCR. RNA-sequencing was used to determine the fusion genes, and a novel fusion gene PTCH1-PLAG1 was found. Moreover, the fusion gene was confirmed by one-step RT-PCR. Conclusion: Our study indicates that one-step RT-PCR displays a reliable tool to detect fusion genes with the advantage of high accuracy and low cost. Moreover, it is a great tool to identify novel fusion genes. Overall, it provides useful information for molecular pathological diagnosis and improves the diagnosis rate of STSs.Copyright © 2023 Song, Zhang, Wang, Xia, Guo, Cao, Xin, Cheng, Liu, Jia and Li.