A patient-derived xenograft and a cell line derived from it form a useful preclinical model for small bowel adenocarcinoma
CANCER MEDICINE
Authors: Yamano, Tomoki; Kubo, Shuji; Tomita, Naohiro
Abstract
Basic and clinical studies on small bowel adenocarcinoma (SBA) are limited due to the rare nature of this cancer. We established a patient-derived xenograft (PDX) model from the tumor tissue of an advanced SBA patient with liver and peritoneal metastasis, and a cell line from the PDX. In the PDX model, compared to the control group, 5-fluorouracil (5-FU) treatment resulted in statistically significant tumor growth inhibition (TGI), while oxaliplatin (OHP) and irinotecan had no significant inhibitory effects. In combination with 5-FU, OHP showed the highest rate of TGI. The IC50 for OHP was significantly lower than those for paclitaxel, gemcitabine, and trifluorothymidine in the PDX-derived cell line when compared to in HT29, a colon cancer cell line. Genetic analysis of the patient tumor, PDX tumor, and the cell line demonstrated consistency in the microsatellite status and mutations in TP53, APC, HRAS, CSF1R, FGFR3, FLT3, PDGFRA, and RET genes. However, the PDX tumor alone had additional mutations, indicating that the PDX-derived cell line may support the unstable genetic status of the PDX. Our findings confirmed the effectiveness of the combination of OHP and 5-FU, which is a common treatment for advanced SBA and advanced colorectal cancer, in a preclinical model. This preclinical model of SBA can help in further understanding the biology of SBA.
Genomic landscape of metastatic papillary thyroid carcinoma and novel biomarkers for predicting distant metastasis
CANCER SCIENCE
Authors: Lan, Xiabin; Bao, Hua; Ge, Xinyang; Cao, Jun; Fan, Xiaojun; Zhang, Qihong; Liu, Kaihua; Zhang, Xian; Tan, Zhuo; Zheng, Chuanming; Wang, Ao; Chen, Chao; Zhu, Xin; Wang, Jiafeng; Xu, Jiajie; Zhu, Xuhang; Wu, Xue; Wang, Xiaonan; Shao, Yang; Ge, Minghua
Abstract
Papillary thyroid carcinoma (PTC) is the most common malignancy of the thyroid gland, with a relatively high cure rate. Distant metastasis (DM) of PTC is uncommon, but when it occurs, it significantly decreases the survival of PTC patients. The molecular mechanisms of DM in PTC have not been systematically studied. We performed whole exome sequencing and GeneseeqPrime (425 genes) panel sequencing of the primary tumor, plasma and matched white blood cell samples from 20 PTC with DM and 46 PTC without DM. We identified somatic mutations, gene fusions and copy number alterations and analyzed their relationships with DM of PTC. BRAF-V600E was identified in 73% of PTC, followed by RET fusions (14%) in a mutually exclusive manner (P < 0.0001). We found that gene fusions (RET, ALK or NTRK1) (P < 0.01) and chromosome 22q loss (P < 0.01) were independently associated with DM in both univariate and multivariate analyses. A nomogram model consisting of chromosome 22q loss, gene fusions and three clinical variables was built for predicting DM in PTC (C-index = 0.89). The plasma circulating tumor DNA (ctDNA) detection rate in PTC was only 38.9%; however, it was significantly associated with the metastatic status (P = 0.04), tumor size (P = 0.001) and invasiveness (P = 0.01). In conclusion, gene fusions and chromosome 22q loss were independently associated with DM in PTC and could serve as molecular biomarkers for predicting DM. The ctDNA detection rate was low in non-DM PTC but significantly higher in PTC with DM.