Secondary leiomyosarcoma of the nasal cavity in a treated patient with possible hereditary retinoblastoma with germline reciprocal translocation of RB1 and DMXL1 and somatic TP53 mutation: A case report

• Published in: Molecular and clinical oncology 2023-08, Vol.19 (2), Article 65
• Main Authors: Yagi, Toshinari, Nakamura, Harumi, Kukita, Yoji, Wakamatsu, Toru, Tamiya, Hironari, Nakai, Shou, Watanabe, Makiyo, Kakunaga, Shigeki, Takami, Haruna, Suzuki, Rie, Takenaka, Satoshi, Hashii, Yoshiko
• Format: Article
• Language: English
• Subjects: Antimitotic agents; Antineoplastic agents; Automobile industry; Cancer therapies; Care and treatment; Case Report; Case reports; Chemotherapy; Endoscopy; Genes; Genetic aspects; Leiomyosarcoma; Lymphatic system; Medical equipment and supplies industry; Medical test kit industry; Metastasis; Mutation; Oncology; Radiation therapy; Radiotherapy; Retinoblastoma; RNA; Sarcoma; Scientific equipment and supplies industry; Tumor proteins; Vision disorders in children
• ISSN: 2049-9450; 2049-9469
• DOI: 10.3892/mco.2023.2661

Retinoblastoma is a common primary intraocular malignant tumor that affects infants and young children. Radiation therapy for hereditary retinoblastoma increases the risk of secondary malignancy. The present report discusses the case of a retinoblastoma survivor who developed secondary leiomyosarcoma 42 years after receiving radiation therapy. The retinoblastoma of the patient was unilateral, and the patient had no family history of the disease. RNA and DNA panel sequencing of the leiomyosarcoma tissue was performed to elucidate the molecular mechanism of this secondary malignancy. The RNA panel sequencing detected a germline reciprocal translocation of RB1 and DMXL1, leading to a diagnosis of possible hereditary retinoblastoma. Furthermore, it detected a somatic fusion gene (RAD51-KNL1). The DNA panel sequencing identified various germline or somatic variants, including a somatic splice acceptor site mutation of TP53. We hypothesized that the molecular mechanism of the secondary malignancy of this patient was the combination of a germline reciprocal translocation of RB1 and DMXL1 and the accumulation of various somatic mutations containing the splice acceptor site mutation of TP53, which ultimately led to the development of a secondary leiomyosarcoma. Further prospective investigations are necessary to fully understand the role of reciprocal translocation of RB1 and DMXL1 or other mutations in the tumorigenesis of second malignancies in patients with hereditary retinoblastoma.