Mutational analysis of uterine cervical cancer that survived multiple rounds of radiotherapy

// Endang Nuryadi 1, 2, * , Yasushi Sasaki 3, * , Yoshihiko Hagiwara 1, * , Tiara Bunga Mayang Permata 1, 2 , Hiro Sato 1 , Shuichiro Komatsu 1 , Yuya Yoshimoto 1 , Kazutoshi Murata 1 , Ken Ando 1 , Nobuteru Kubo 1 , Noriyuki Okonogi 1 , Yosuke Takakusagi 1 , Akiko Adachi 1 , Mototaro Iwanaga 1 , Keisuke Tsuchida 1 , Tomoaki Tamaki 1 , Shin-ei Noda 1 , Yuka Hirota 1 , Atsushi Shibata 4 , Tatsuya Ohno 5 , Takashi Tokino 3 , Takahiro Oike 1 and Takashi Nakano 1, 5 1 Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan 2 Department of Radiotherapy, Dr. Cipto Mangunkusumo National General Hospital, Jakarta, Indonesia 3 Department of Medical Genome Sciences, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan 4 Education and Research Support Center, Gunma University Graduate School of Medicine, Gunma, Japan 5 Gunma University Heavy Ion Medical Center, Gunma, Japan * These authors contributed equally to this work Correspondence to: Takahiro Oike, email: oiketakahiro@gmail.com Keywords: uterine cervical cancer; radioresistance; next-generation sequencing; KRAS; SMAD4 Received: February 16, 2018      Accepted: August 04, 2018      Published: August 24, 2018 ABSTRACT Radiotherapy is an essential component of cancer therapy. Despite advances in cancer genomics, the mutation signatures of radioresistant tumors have not yet been fully elucidated. To address this issue, we analyzed a unique set of clinical specimens from a uterine cervical cancer that repeatedly locally recurred after multiple rounds of radiotherapy. Exon sequencing of 409 cancer-related genes in the treatment-naive tumor and the tumors that recurred after initial and secondary radiotherapy identified (i) activating mutations in PIK3CA and KRAS , and putative inactivating mutations in SMAD4 , as trunk mutation signatures that persisted over the clinical course; and (ii) mutations in KMT2A , TET1 , and NLRP1 as acquired mutation signatures observed only in recurrent tumors after radiotherapy. Comprehensive mining of published in vitro genomics data pertaining to radiosensitivity revealed that simultaneous mutations in KRAS and SMAD4 , which have not been described previously in uterine cervical cancer, are associated with cancer cell radioresistance. The association between this mutation signature and radioresistance was validated by isogenic cell-based experiments. These results provide proof-of-principle for the analytical pipeline employed in this study, which explores clinically relevant mutation signatures for radioresistance, and demonstrate that this approach is worth pursuing with larger cohorts in the future.