Establishment, characterization, and genetic profiling of patient-derived osteosarcoma cells from a patient with retinoblastoma.

Osteosarcoma is the most common malignant bone cancer in pediatric patients. Patients who respond poorly to chemotherapy experience worse clinical outcomes with a high mortality rate. The major challenge is the lack of effective drugs for these patients. To introduce new drugs for clinical approval, preclinical studies based on in vitro models must demonstrate the potency of the tested drugs, enabling the drugs to enter phase 1 clinical trials. Patient-derived cell culture is a promising testing platform for in vitro studies, as they more accurately recapitulate cancer states and genetic profiles compared to cell lines. In the present study, we established patient-derived osteosarcoma cells (PDC) from a patient who had previously been diagnosed with retinoblastoma. We identified a new variant of a germline mutation in the RB1 gene in the tissue of the patient. The biological effects of this PDC were studied to observe whether the cryopreserved PDC retained a feature of fresh PDC. The cryopreserved PDC preserved the key biological effects, including cell growth, invasive capability, migration, and mineralization, that define the conserved phenotypes compared to fresh PDC. From whole genome sequencing analysis of osteosarcoma tissue and patient-derived cells, we found that cryopreserved PDC was a minor population in the origin tissue and was selectively grown under the culture conditions. The cryopreserved PDC has a high resistance to conventional chemotherapy. This study demonstrated that the established cryopreserved PDC has the aggressive characteristics of osteosarcoma, in particular the chemoresistance phenotype that might be used for further investigation in the chemoresistant mechanism of osteosarcoma. In conclusion, the approach we applied for primary cell culture might be a promising method to generate in vitro models for functional testing of osteosarcoma.

Characterization of Cell-Free DNA Size Distribution in Osteosarcoma Patients.

PURPOSE: Cell-free DNA (cfDNA) analysis is a powerful tool for noninvasively predicting patient outcomes. We analyzed the size distribution of cfDNA and assessed its prognostic and diagnostic values in an osteosarcoma cohort. EXPERIMENTAL DESIGN: The fragment size distribution and level of cfDNA were analyzed in 15 healthy donors and 50 patients with osteosarcoma using automated capillary electrophoresis. The prognostic performance of cfDNA size analysis was assessed using univariate and multivariable analyses. By performing whole-genome sequencing of matched cfDNA and osteosarcoma tissue samples, we investigated the correlation between the size and mutation profiles of cfDNA and the mutation concordance between cfDNA and paired tissue tumors. RESULTS: The size of cfDNA fragments in patients with osteosarcoma was significantly shorter than in healthy donors, with the integrative analysis of size distribution and level of cfDNA achieving a high specificity and sensitivity of 100%. The short cfDNA fragment (150-bp cut-off) was an independent prognostic predictor in this osteosarcoma cohort [HR, 9.03; 95% confidence interval (CI), 1.13-72.20; P = 0.038]. Shortened cfDNA fragments were found to be a major source of mutations. Enrichment of cfDNA fragments with less than or equal to 150 bp by in silico size selection remarkedly improved the detection of copy-number variation signals up to 2.3-fold when compared with total cfDNA, with a higher concordance rate with matched osteosarcoma tissue. CONCLUSIONS: This finding demonstrated the potential of cfDNA size profiling in the stratification of poor prognostic patients with osteosarcoma. The short fragments of cfDNA are a promising source for boosting the detection of significant mutations in osteosarcoma. See related commentary by Weiser et al., p. 2017.

An analysis of the incidence and survival rates of bone sarcoma patients in thailand: reports from population-based cancer registries 2001-2015.

BACKGROUND: Epidemiology data from population-based cancer registries (PBCR) can be very valuable in the development of health policy and for improving the quality of cancer control strategies. METHODS: This study analyzed the incidence of bone sarcomas in Thailand during 2001 - 2015 by analyzing data obtained from 5 PBCRs across country. Incidence rates per million person-years by sex, histological subtype, primary site and 5-year age group were calculated. Age-standardized incidence rates (ASR) were adjusted using the WHO's World Standard Population and comparisons between populations were done using standardized rate ratios (SRR). Incidence trends were evaluated using Joinpoint Trend Analysis. Survival rates were analyzed using STATA. RESULTS: The ASR of bone sarcomas in Thailand was 5.1/106 person-years, with an estimated 328 newly diagnosed bone sarcomas per year for the country overall. Osteosarcoma (52.5%), chondrosarcoma (18%), Ewing's sarcoma (11.6%), giant cell tumor (4.8%) and chordoma (4.7%) were the most common malignant bone tumors, representing 91.5% of all bone sarcomas. Bone sarcoma has a predilection for males (1.29:1) and an age-specific bimodal rate pattern closely related to the major histological subtypes, osteosarcoma. One- and five-year survival rates of Thai patients with bone sarcoma were 74% and 52%, respectively. Survival rates of bone sarcomas, particularly osteosarcoma, were lower than the rates reported from the United States, Europe and Japan. CONCLUSION: The lower overall survival rate of bone sarcoma represented the gap of bone sarcoma control program in Thailand. That indicates the need for improvement in health promotion, treatment process and chemotherapy for bone sarcoma patients in the future.

In search of TP53 mutational hot spots for Li-Fraumeni syndrome in Asian populations.

OBJECTIVE: Germline mutations of the TP53 tumour suppressor gene are the only known cause of the hereditary autosomal disorder called Li-Fraumeni syndrome (LFS). However, little information is available about TP53 pathogenic variants in Asian LFS patients, making it difficult to provide precise genetic counselling with regard to long-term cancer risk. We conducted a systematic review to gather relevant case-control studies exploring the association between TP53 polymorphisms and the incidence of cancer belonging to the LFS spectrum in Asian populations. METHOD: Systematic review and meta-analysis. The odds ratio was used as a summary effect measure to quantify the strength of the association between TP53 polymorphisms and cancer risk by means of random-effects meta-analysis. RESULTS: In total, 16 studies were included in this systematic review, with 13 studies (involving 10,645 cases and 28,288 controls) that enabled meta-analysis. The majority of the studies focused on a single-nucleotide variation at codon 72 in exon 4 (c.215C>G, p.Arg72Pro, rs1042522). Therefore, we tested either dominant, co-dominant, recessive, or heterozygous models and found that the p.Arg72Pro was not significantly associated with increased cancer risk in any of the models. CONCLUSION: We found the number of studies on cancers belonging to the LFS spectrum in Asia is very small. Thus, at the present time a meta-analysis approach is somewhat useful to identify germline TP53 mutations as potential markers of hereditary cancer associated with LFS in Asian populations.

A novel loss-of-function mutation of PBK associated with human kidney stone disease.

Kidney stone disease (KSD) is a prevalent disorder that causes human morbidity worldwide. The etiology of KSD is heterogeneous, ranging from monogenic defect to complex interaction between genetic and environmental factors. Since mutations of genes responsible for KSD in a majority of families are still unknown, our group is identifying mutations of these genes by means of genomic and genetic analyses. In this study, we identified a novel loss-of-function mutation of PBK, encoding the PDZ binding kinase, that was found to be associated with KSD in an affected Thai family. Glycine (Gly) substituted by arginine (Arg) at position 43 (p.Gly43Arg) in PBK cosegregated with the disease in affected members of this family, but was absent in 180 normal control subjects from the same local population. Gly43 is highly evolutionarily conserved in vertebrates, and its substitution affects protein structure by alterations in H-bond forming patterns. This p.Gly43Arg substitution results in instability of the variant PBK protein as examined in HEK293T cells. The variant PBK protein (p.Gly43Arg) demonstrated decreased kinase activity to phosphorylate p38 MAPK as analyzed by immunoblotting and antibody microarray techniques. Taken together, these findings suggest a possible new mechanism of KSD associated with pathogenic PBK variation.