Renal cell carcinoma is a heterogeneous kidney cancer, and over 403,000 cases were reported worldwide in 2018. Current methods for studying renal cell carcinoma are limited to two-dimensional (2D) culture of primary cell lines and patient-derived xenograft models. Numerous studies have suggested that 2D culture poorly represents the diversity, heterogeneity, and drug-resistance of primary tumors. The time and cost associated with patient-derived xenograft models poses a realistic barrier to their clinical utility. As a biomimetic model, patient-derived three-dimensional (3D) organoid culture can overcome these disadvantages and bridge the gap between in vitro cell culture and in vivo patient-derived xenograft models. Here, we establish a patient-derived 3D organoid culture system for clear cell renal cell carcinoma and demonstrate the biomimetic characteristics of our model with respect to both primary kidney cancer and conventional 2D culture. Normal renal tissues and tumor tissues were collected from patients with clear cell renal cell carcinoma. The dissociated cells were cultured as conventional 2D culture and 3D organoid culture. The biomimetic characteristic of the two cultures were compared. Compared with 2D culture, the 3D organoid cultures retained the characteristic lipid-rich, clear cell morphology of clear cell renal cell carcinoma. Carbonic anhydrase 9 and vimentin were validated as biomarkers of renal cell carcinoma. Expression of the two validated biomarkers was more enhanced in 3D organoid culture. Patient-derived 3D organoid culture retains the characteristics of renal cell carcinoma with respect to morphology and biomarker expression.

Background/Objectives: Oligodontia, the absence of six or more teeth excluding third molars, is a rare genetic condition, unlike hypodontia (missing one or more teeth), which is a relatively common human disease. Methods: To identify the genetic etiology of nonsyndromic oligodontia (NSO) families, we performed mutational analysis and investigated the functional effects of identified EDAR mutations. Whole-exome sequencing was conducted on recruited families with NSO. Bioinformatic analysis identified mutations in oligodontia-causing candidate genes, which were confirmed by Sanger sequencing and segregation within families. The impact of EDAR mutations on the EDA signaling pathway was assessed using luciferase activity analysis. Results: EDAR mutations were identified in three NSO families. A homozygous missense EDAR mutation (NM_022336.4: c.319A>G p.(Met107Val)) was found in the singleton proband of family 1. The proband of family 2 carried compound heterozygous EDAR mutations: a maternal missense mutation (c.319A>G p.(Met107Val)) and a paternal missense variant (c.1270G>A p.(Val424Met)). The proband of family 3 had heterozygous EDAR mutations: a maternal missense mutation (c.389T>A p.(Ile130Asn)) and paternal intronic variants in cis (c.[357-4G>A;440+50C>T]). Luciferase assays confirmed reduced transcriptional activity for all identified missense mutations, while splicing assays revealed altered splicing patterns. Conclusions: In conclusion, recessive EDAR mutations, including novel ones, were identified in NSO families, and their pathological mechanism was explored through transcriptional activity measurements.