Association between risk factors, molecular features and CpG island methylator phenotype colorectal cancer among different age groups in a Taiwanese cohort.

BACKGROUND: CpG island methylator phenotype (CIMP) represents a carcinogenesis pathway of colorectal cancer (CRC) and the association between CIMP CRC, molecular features and risk factors in East Asian population is less studied. METHODS: We prospectively enrolled newly diagnosed CRC patients at the National Taiwan University Hospital. Clinicopathological data and risk factors for CRC were collected during interview. The tumour samples were subjected to CIMP, RAS/BRAF mutation and microsatellite instability tests. CIMP-high was determined when ≧3 methylated loci of p16, MINT1, MINT2, MINT31 and MLH1 were identified. Multivariate logistic regression was used to evaluate the association between risk factors and CIMP-high CRC. RESULTS: Compared with CIMP-low/negative CRC, CIMP-high CRC was associated with more stage IV disease, BRAF V600E mutation and high body mass index (BMI ≧ 27.5 kg/m2) in younger patients (age < 50 y), and more right-sided tumour, BRAF V600E mutation, MSI-high and colorectal polyp in elder patients (age ≧ 50 y). Multivariate analyses showed that BMI ≧27.5 kg/m2 was significantly associated with CIMP-high CRC in younger patients. CONCLUSIONS: We identified distinct clinicopathological features for CIMP-high CRC among different age groups in Taiwan. Our data suggest the association between BMI ≧27.5 kg/m2 and CIMP-high CRC in patients younger than 50 years.

Prediction Model for Audiological Outcomes in Patients With GJB2 Mutations.

OBJECTIVES: Recessive mutations in GJB2 are the most common genetic cause of sensorineural hearing impairment (SNHI) in humans. SNHI related to GJB2 mutations demonstrates a wide variation in audiological features, and there has been no reliable prediction model for hearing outcomes until now. The objectives of this study were to clarify the predominant factors determining hearing outcome and to establish a predictive model for SNHI in patients with GJB2 mutations. DESIGN: A total of 434 patients confirmed to have biallelic GJB2 mutations were enrolled and divided into three groups according to their GJB2 genotypes. Audiological data, including hearing levels and audiogram configurations, were compared between patients with different genotypes. Univariate and multivariate generalized estimating equation (GEE) analyses were performed to analyze longitudinal data of patients with multiple audiological records. RESULTS: Of the 434 patients, 346 (79.7%) were homozygous for the GJB2 p.V37I mutation, 55 (12.7%) were compound heterozygous for p.V37I and another GJB2 mutation, and 33 (7.6%) had biallelic GJB2 mutations other than p.V37I. There was a significant difference in hearing level and the distribution of audiogram configurations between the three groups. Multivariate GEE analyses on 707 audiological records of 227 patients revealed that the baseline hearing level and the duration of follow-up were the predominant predictors of hearing outcome, and that hearing levels in patients with GJB2 mutations could be estimated based on these two parameters: (Predicted Hearing Level [dBHL]) = 3.78 + 0.96 × (Baseline Hearing Level [dBHL]) + 0.55 × (Duration of Follow-Up [y]). CONCLUSION: The baseline hearing level and the duration of follow-up are the main prognostic factors for outcome of GJB2-related SNHI. These findings may have important clinical implications in guiding follow-up protocols and designing treatment plans in patients with GJB2 mutations.

CpG Island Methylator Phenotype May Predict Poor Overall Survival of Patients with Stage IV Colorectal Cancer.

OBJECTIVE: We aimed to study the prognostic role of CpG island methylator phenotype (CIMP) in patients with different stages of colorectal cancer (CRC). MATERIAL AND METHODS: We analyzed CIMP in stage I-IV CRC specimens from patients who were diagnosed between 2005 and 2013. CIMP status was determined using a 5-gene MethyLight-based assay. The clinicopathologic characteristics were reviewed and the overall survival (OS) was compared between patients with CIMP-high CRC and those with CIMP-low/negative CRC. RESULTS: Among 450 CRC specimens with successfully determined CIMP statuses, 74 (16.4%) were CIMP-high CRC. Although there was no difference in OS between patients with CIMP-high and CIMP-low/negative CRC across all stages (p = 0.4526), intriguingly, patients with stage IV CIMP-high CRC had significantly worse OS than those with stage IV CIMP-low/negative CRC (p = 0.0047). In a multivariate analysis, CIMP status remained an independent prognostic factor for overall mortality (HR = 5.60, 95% CI: 2.12-14.79, p = 0.0005) in metastatic CRC after adjusting for clinicopathologic variables and anti-cancer therapies. CONCLUSION: Our results revealed that the presence of CIMP independently predicts poor OS in patients with stage IV CRC.

Clinical mutational profiling and categorization of BRAF mutations in melanomas using next generation sequencing.

BACKGROUND: Analysis of melanomas for actionable mutations has become the standard of care. Recently, a classification scheme has been proposed that categorizes BRAF mutations based on their mechanisms for activation of the MAPK pathway. METHODS: In this analysis BRAF, KIT, NRAS, and PIK3CA mutations were examined by next generation sequencing (NGS) in 446 melanomas in a clinical diagnostic setting. KRAS and HRAS were also analyzed to elucidate coexisting BRAF and RAS mutations. BRAF mutations were categorized into class-1 (kinase-activated, codon 600), class-2 (kinase-activated, non-codon 600) and class-3 (kinase-impaired), based on the newly proposed classification scheme. RESULTS: NGS demonstrated high analytic sensitivity. Among 355 mutations detected, variant allele frequencies were 2-5% in 21 (5.9%) mutations and 2-10% in 47 (13%) mutations. Mutations were detected in BRAF (42%), NRAS (25%), KIT (4.9%) and PIK3CA (2.7%). The incidence of class-1, class-2 and class-3 mutations were 33% (26% p.V600E and 6.1% p.V600K), 3.1 and 4.9% respectively. With a broader reportable range of NGS, class-1, class-2 and class-3 mutations accounted for 77, 7.4 and 12% of all BRAF mutations. Class-3 mutations, commonly affecting codons 594, 466 and 467, showed a higher incidence of coexisting RAS mutations, consistent with their RAS-dependent signaling. Significant association with old age and primary tumors of head/neck/upper back suggest chronic solar damage as a contributing factor for melanomas harboring BRAF p.V600K or class-3 mutations. CONCLUSION: This study categorizes the range, frequency, coexisting driver mutations and clinical characteristics of the three classes of BRAF mutations in a large cohort of melanomas in a clinical diagnostic setting. Further prospective studies are warranted to elucidate the clinical outcomes and benefits of newly developed targeted therapy in melanoma patients carrying each class of BRAF mutation.

Epithelioid Trophoblastic Tumor Around an Abdominal Cesarean Scar: A Pathologic and Molecular Genetic Analysis.

Epithelioid trophoblastic tumor (ETT) is a rare chemoresistant gestational trophoblastic neoplasm that typically presents as an intrauterine lesion. To our knowledge, no isolated abdominal wall ETT around a Cesarean scar has been reported. Here we describe a 54-yr-old woman with a complex obstetric history who presented with a solitary abdominal wall tumor adjacent to the abdominal Cesarean section scar. The tumor demonstrated typical morphologic and immunophenotypic features of ETT. The gestational origin of the tumor was confirmed by microsatellite genotyping. The tumor enlarged despite the patient undergoing multiagent chemotherapy. Whole-exome sequencing was performed to explore the mechanisms underlying chemoresistance. The ATP-binding cassette subfamily B member 1 (ABCB1) 3435CC genotype, and a putative deleterious x-ray cross-complementing group 4 (XRCC4) Ala73Pro mutations were found. In conclusion, ETT may present as a solitary abdominal wall lesion and microsatellite genotyping could facilitate the determination of its gestational origin. More studies are required to provide mechanistic insights into the chemoresistance of ETT.

A panel of 130 autosomal single-nucleotide polymorphisms for ancestry assignment in five Asian populations and in Caucasians.

Ancestry informative single-nucleotide polymorphism (AISNP) panels for differentiating between East and Southeast Asian populations are scarce. This study aimed to identify AISNPs for ancestry assignment of five East and Southeast Asian populations, and Caucasians. We analyzed 145 autosomal SNPs of the 627 DNA samples from individuals of six populations (234 Taiwanese Han, 91 Filipinos, 79 Indonesians, 60 Thais, 71 Vietnamese, and 92 Caucasians) using arrays. The multiple logistic regression model and a multi-tier approach were used for ancestry classification. We observed that 130 AISNPs were effective for classifying the ethnic origins with fair accuracy. Among the 130 AISNPs, 122 were useful for stratification between these five Asian populations and 64 were effective for differentiating between Caucasians and these Asian populations. For differentiation between Caucasians and Asians, an accuracy rate of 100% was achieved in these 627 subjects with 50 optimal AISNPs among the 64 effective SNPs. For classification of the five Asian populations, the accuracy rates of ancestry inference using 20 to 57 SNPs for each of the two Asian populations ranged from 74.1% to 100%. Another 14 degraded DNA samples with incomplete profiling were analyzed, and the ancestry of 12 (85.7%) of those subjects was accurately assigned. We developed a 130-AISNP panel for ethnic origin differentiation between the five East and Southeast Asian populations and Caucasians. This AISNP set may be helpful for individual ancestral assignment of these populations in forensic casework.

Genotyping of 75 SNPs using arrays for individual identification in five population groups.

Single nucleotide polymorphism (SNP) typing offers promise to forensic genetics. Various strategies and panels for analyzing SNP markers for individual identification have been published. However, the best panels with fewer identity SNPs for all major population groups are still under discussion. This study aimed to find more autosomal SNPs with high heterozygosity for individual identification among Asian populations. Ninety-six autosomal SNPs of 502 DNA samples from unrelated individuals of five population groups (208 Taiwanese Han, 83 Filipinos, 62 Thais, 69 Indonesians, and 80 individuals with European, Near Eastern, or South Asian ancestry) were analyzed using arrays in an initial screening, and 75 SNPs (group A, 46 newly selected SNPs; groups B, 29 SNPs based on a previous SNP panel) were selected for further statistical analyses. Some SNPs with high heterozygosity from Asian populations were identified. The combined random match probability of the best 40 and 45 SNPs was between 3.16 × 10(-17) and 7.75 × 10(-17) and between 2.33 × 10(-19) and 7.00 × 10(-19), respectively, in all five populations. These loci offer comparable power to short tandem repeats (STRs) for routine forensic profiling. In this study, we demonstrated the population genetic characteristics and forensic parameters of 75 SNPs with high heterozygosity from five population groups. This SNPs panel can provide valuable genotypic information and can be helpful in forensic casework for individual identification among these populations.

Performance characteristics of next-generation sequencing in clinical mutation detection of colorectal cancers.

Activating mutations in downstream genes of the epidermal growth factor receptor (EGFR) pathway may cause anti-EGFR resistance in patients with colorectal cancers. We present performance characteristics of a next-generation sequencing assay designed to detect such mutations. In this retrospective quality assessment study, we analyzed mutation detected in the KRAS, NRAS, BRAF, and PIK3CA genes by a clinically validated next-generation sequencing assay in 310 colorectal cancer specimens. Tumor cellularity and mutant allele frequency were analyzed to identify tumor heterogeneity and mutant allele-specific imbalance. Next-generation sequencing showed precise measurement of mutant allele frequencies and detected 23% of mutations with 2-20% mutant allele frequencies. Of the KRAS mutations detected, 17% were outside of codons 12 and 13. Among PIK3CA mutations, 48% were outside of codons 542, 545, and 1047. The percentage of tumors with predicted resistance to anti-EGFR therapy increased from 40% when testing for only mutations in KRAS exon 2 to 47% when testing for KRAS exons 2-4, 48% when testing for KRAS and NRAS exons 2-4, 58% when including BRAF codon 600 mutations, and 59% when adding PIK3CA exon 20 mutations. Right-sided colorectal cancers carried a higher risk of predicted anti-EGFR resistance. A concomitant KRAS mutation was detected in 51% of PIK3CA, 23% of NRAS, and 33% of kinase-impaired BRAF-mutated tumors. Lower than expected mutant allele frequency indicated tumor heterogeneity, while higher than expected mutant allele frequency indicated mutant allele-specific imbalance. Two paired neuroendocrine carcinomas and adjacent adenomas showed identical KRAS mutations, but only PIK3CA mutations in neuroendocrine carcinomas. Next-generation sequencing is a robust tool for mutation detection in clinical laboratories. It demonstrates high analytic sensitivity and broad reportable range, and it provides simultaneous detection of concomitant mutations and a quantitative measurement of mutant allele frequencies to predict tumor heterogeneity and mutant allele-specific imbalance.

Aberrant expression of annexin A10 is closely related to gastric phenotype in serrated pathway to colorectal carcinoma.

Annexin A10 (ANXA10) is a member of the ANX family that is normally expressed in gastric mucosa. ANXA10 was recently observed to be upregulated in sessile serrated adenoma, a precursor to microsatellite-unstable colorectal cancer. We investigated the use of ANXA10 in diagnosing colorectal carcinoma. In an immunohistochemical analysis, the intensity and quantity of ANXA10, MUC5AC, MUC6 and CDX2 in 123 colorectal carcinomas were graded. We determined the molecular status of BRAF and KRAS mutations, as well as the microsatellite instability status and the CpG island methylator phenotype in all colorectal carcinomas, and subcategorized into four molecular subgroups according to the molecular derangements. Nuclear ANXA10 staining was present in 36 colorectal carcinomas, exhibiting a strong significant association with the BRAF mutation status (P<0.0001) and positive CpG island methylator phenotype (P<0.0001), and a borderline significant association with high levels of microsatellite instability (P=0.072). The ANXA10-positive colorectal carcinomas were frequently positive for MUC5AC and MUC6, and were associated with absent or reduced CDX2 expression (all P<0.0001). According to a classification and regression tree analysis, ANXA10 is a superior marker for the molecular subtyping of colorectal carcinomas and represents a specific marker for colorectal cancers of the serrated pathway. Our results indicated that ANXA10 expression is implicated in gastric programming in serrated-pathway-associated colorectal carcinoma. ANXA10-positive colorectal carcinoma is highly associated with the molecular features of the serrated neoplasia pathway.

Immunohistochemical study of endometrial high-grade endometrioid carcinoma with or without a concurrent low-grade component: implications for pathogenetic and survival differences.

AIMS: To compare the clinical and pathogenetic differences between high-grade (HG) endometrioid carcinomas with and without concurrent low-grade (LG) components. METHODS AND RESULTS: The expression of ARID1A, PTEN, p53 and mismatch repair (MMR) proteins in HG endometrioid carcinomas without (n = 19) or with (n = 22) concurrent LG endometrioid carcinomas was studied by immunohistochemistry. Microsatellite instability (MSI) was also tested in 31 cases. The frequencies of ARID1A loss, PTEN loss, MMR deficiency or MSI and aberrant p53 expression were 58%, 37%, 37% and 47% in pure HG tumours, and 77%, 45%, 55% and 32% in HG tumours with concurrent LG components (P = 0.07 for ARID1A; P > 0.1 for other proteins). Pure HG tumours had a higher frequency of the type II phenotype (positive for ARID1A, PTEN and MMR proteins; aberrant p53 expression) than HG tumours with concurrent LG components (21% versus 5%) (P = 0.2). The 5-year overall survival rate was worse for pure HG tumours (61.7%) than for HG tumours with concurrent LG components (93.3%) (P = 0.07). CONCLUSIONS: HG endometrioid carcinomas are heterogeneous in pathogenesis: some arise from LG endometrioid carcinomas via the type I pathway, whereas others may arise de novo through either the type I pathway or the type II pathway, and have a different prognosis. Thus, HG endometrioid carcinomas should be subclassified properly and treated accordingly.

Ovarian and endometrial endometrioid adenocarcinomas have distinct profiles of microsatellite instability, PTEN expression, and ARID1A expression.

AIMS: To understand the role of and differences in molecular alterations between endometrial and ovarian endometrioid adenocarcinomas. METHODS AND RESULTS: We investigated the microsatellite status of 26 ovarian endometrioid adenocarcinomas (OVEMs), 42 endometrial endometrioid adenocarcinomas (EMCAs), and 19 concurrent (endometrial and ovarian) endometrioid adenocarcinomas. We evaluated the expression of the mismatch repair proteins, PTEN and ARID1A, and mutations of PTEN, KRAS, CTNNB1, and PIK3CA. High levels of microsatellite instability (MSI-H) were present in one of 26 OVEMs, 12 of 42 EMCAs, and four of 19 concurrent endometrioid adenocarcinomas. Only four of 19 concurrent endometrioid adenocarcinomas showed identical molecular alterations in their endometrial and ovarian components. Loss of ARID1A or loss of PTEN expression, and MSI-H, were more common in EMCAs than OVEMs (P = 0.044, P = 0.004, and P = 0.012, respectively). MSI-H in endometrial endometrioid adenocarcinomas was also related to loss of ARID1A expression (P < 0.001). In the cohort of MSI-H endometrioid adenocarcinomas involving the endometrium (n = 16), MSH6-deficient cases showed higher frequencies of CTNNB1 and PIK3CA mutations (P = 0.008 and P = 0.036, respectively), but lower frequencies of KRAS mutation (P = 0.011), than PMS2-deficient cases. CONCLUSIONS: The different frequencies of molecular genetic alterations between endometrial endometrioid adenocarcinomas and ovarian endometrioid adenocarcinomas imply that distinct processes may be involved in their tumorigenesis or tumour progression.

Clinical detection and categorization of uncommon and concomitant mutations involving BRAF.

BACKGROUND: Selective BRAF inhibitors, vemurafenib and dabrafenib, and the MEK inhibitor, trametinib, have been approved for treatment of metastatic melanomas with a BRAF p.V600E mutation. The clinical significance of non-codon 600 mutations remains unclear, in part, due to variation of kinase activity for different mutants. METHODS: In this study, we categorized BRAF mutations according to the reported mutant kinase activity. A total of 1027 lung cancer, colorectal cancer or melanoma specimens were submitted for clinical mutation detection by next generation sequencing. RESULTS: Non-codon 600 mutations were observed in 37% of BRAF-mutated tumors. Of all BRAF mutants, 75% were kinase-activated, 15% kinase-impaired and 10% kinase-unknown. The most common kinase-impaired mutant involves codon 594, specifically, p.D594G (c.1781A > G) and p.D594N (c.1780G > A). Lung cancers showed significantly higher incidences of kinase-impaired or kinase-unknown mutants. Kinase-impaired BRAF mutants showed a significant association with concomitant activating KRAS or NRAS mutations, but not PIK3CA mutations, supporting the reported interaction of these mutations. CONCLUSIONS: BRAF mutants with impaired or unknown kinase activity as well as concomitant kinase-impaired BRAF mutations and RAS mutations were detected in lung cancers, colorectal cancers and melanomas. Different therapeutic strategies based on the BRAF mutant kinase activity and the concomitant mutations may be worthwhile.

Improved FLT3 internal tandem duplication PCR assay predicts outcome after allogeneic transplant for acute myeloid leukemia.

Patients with acute myeloid leukemia (AML) who harbor internal tandem duplication (ITD) mutations of the FMS-like tyrosine kinase 3 (FLT3) gene carry a poor prognosis. Although allogeneic transplantation may improve outcomes, relapse occurs frequently. The FLT3/ITD mutation has been deemed an unsuitable minimal residual disease (MRD) marker because it is unstable and because the standard assay for the mutation is relatively insensitive. The FLT3 mutation is undetectable by PCR at pre- or post-transplant time points in many FLT3/ITD AML patients who subsequently relapse after transplant. We report the application of a new technique, tandem duplication PCR (TD-PCR), for detecting MRD in FLT3/ITD AML patients. Between October 2004 and January 2012, 54 FLT3/ITD AML patients in remission underwent transplantation at our institution. Of 37 patients with available day 60 marrow samples, 28 (76%) were assessable for MRD detection. In seven of 28 patients (25%), the FLT3/ITD mutation was detectable by TD-PCR but not by standard PCR on day 60. Six of 7 patients (86%) with MRD by TD-PCR have relapsed to date compared with only 2 of 21 patients (10%) who were negative for MRD (P = .0003). The ability to detect MRD by this sensitive technique may provide an opportunity for early clinical intervention.

Fifteen non-CODIS autosomal short tandem repeat loci multiplex data from nine population groups living in Taiwan.

The analysis of autosomal short tandem repeat (STR) loci is a powerful tool in forensic genetics. We developed a multiplex system in which 15 non-Combined DNA Index System autosomal STRs (D3S1744, D4S2366, D8S1110, D10S2325, D12S1090, D13S765, D14S608, Penta E, D17S1294, D18S536, D18S1270, D20S470, D21S1437, Penta D, and D22S683) could be amplified in one single polymerase chain reaction. DNA samples from 1,098 unrelated subjects of nine population groups living in Taiwan, including Taiwanese Han, indigenous Taiwanese of Taiwan Island, Tao, mainland Chinese, Filipinos, Thais, Vietnamese, Indonesians, and Caucasians, were collected and analyzed using this system. The distributions of the allelic frequencies and the forensic parameters of each population group were presented. The combined discrimination power and the combined power of exclusion were high in all population groups tested in this study. A multidimensional scaling plot of these nine population groups based on the Reynolds' genetic distances calculated from 15 autosomal STRs was constructed, and the genetic substructure in this area was presented. In conclusion, this 15 autosomal STR multiplex system provides highly informative STR data and appears useful in forensic casework and parentage testing in different populations.

Double PIK3CA Alterations and Parallel Evolution in Colorectal Cancers.

OBJECTIVES: To demonstrate clinicopathologic features and evaluate the clonality of double PIK3CA alterations in colorectal cancers (CRCs). METHODS: Clonality was examined in 13 CRCs with double PIK3CA alterations (1.7% of CRCs or 9.6% of PIK3CA-mutated CRCs). Multiregional analyses were performed to confirm subclonal PIK3CA alterations. RESULTS: PIK3CA alterations were detected within exon 9 (51%), exon 20 (23%), exon 1 (15%), and exon 7 (6.0%). CRCs with exon 7 alterations showed a significantly higher incidence of double PIK3CA alterations. Most double PIK3CA alterations consisted of a hotpsot alteration and an uncommon alteration; they were often clonal and present within a single tumor population. Multiregional analyses of CRCs with predicted subclonal double-alterations revealed multiclonal CRCs with divergent PIK3CA variant status originating from a common APC- and KRAS-mutated founder lineage of adenoma. CONCLUSIONS: The findings supported multiclonal CRCs resulting from parallel evolution during the progression from adenoma to adenocarcinoma within the mitogen-activated protein kinase pathway, as previously demonstrated, or the mammalian target of rapamycin pathway. Further studies are warranted to elucidate clinical significance and potential targeted therapy for CRC patients with double PIK3CA alterations and impacts on clinical decision-making in patients with multiclonal CRCs harboring divergent PIK3CA mutational status.

Cochlear Implantation Outcomes in Patients with Auditory Neuropathy Spectrum Disorder of Genetic and Non-Genetic Etiologies: A Multicenter Study.

With diverse etiologies and clinical features, the management of pediatric auditory neuropathy spectrum disorder (ANSD) is often challenging, and the outcomes of cochlear implants (CIs) are variable. This study aimed to investigate CI outcomes in pediatric patients with ANSD of different etiologies. Thirty-six children with ANSD who underwent cochlear implantation between 2001 and 2021 were included. Comprehensive etiological analyses were conducted, including a history review, next-generation sequencing-based genetic examinations, and imaging studies using high-resolution computed tomography and magnetic resonance imaging. Serial behavioral and speech audiometry were performed before and after surgery, and the outcomes with CI were evaluated using the Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores. By etiology, 18, 1, 1, and 10 patients had OTOF-related, WFS1-related, OPA1-related, and cochlear nerve deficiency (CND)-related ANSD, respectively. Six patients had no definite etiology. The average CI-aided behavioral threshold was 28.3 ± 7.8 dBHL, and those with CND-related ANSD were significantly worse than OTOF-related ANSD. The patients' median CAP and SIR scores were 6 and 4, respectively. Favorable CI outcomes were observed in patients with certain etiologies of ANSD, particularly those with OTOF (CAP/SIR scores 5-7/2-5), WFS1 (CAP/SIR score 6/5), and OPA1 variants (CAP/SIR score 7/5). Patients with CND had suboptimal CI outcomes (CAP/SIR scores 2-6/1-3). Identifying the etiologies in ANSD patients is crucial before surgery and can aid in predicting prognoses.

Fourteen non-CODIS autosomal short tandem repeat loci multiplex data from Taiwanese.

Interest in the development of polymorphic short tandem repeat (STR) markers unlinked to the CODIS loci is growing among forensic practitioners. We developed a multiplex system in which14 autosomal STR (D3S1744, D4S2366, D8S1110, D12S1090, D13S765, D14S608, Penta E, D17S1294, D18S536, D18S1270, D20S470, D21S1437, Penta D, and D22S683) could be amplified in one single polymerase chain reaction. DNA samples from 572 unrelated Taiwanese Han subjects were analyzed using this 14 STR multiplex system. Thirty parent-child pairs of parentage testing cases with a combined paternity index (CPI) below 1,000 and 32 parent-child pairs with single-step mutations found in AmpFℓSTR Identifiler loci were also recruited for validation of the newly developed system. DNA sequencing was performed for novel STRs and novel alleles found in these subjects. The distributions of allelic frequencies for these autosomal STRs and sequence data, allele nomenclature for the STRs, and forensic parameters are presented. The discrimination power in our multiplex loci ranged from 0.6858 (D18S536) to 0.9168 (Penta E), with a combined discrimination power of 0.999999999. It provides additional power to distinguish the possible single-step mutations in parent-child pairs and improves the ability to prove parentage by increasing the CPI. The combined power of exclusion of these 14 loci in Taiwanese Han in this study was 0.9999995913. In conclusion, this 14-autosomal STRs multiplex system provides highly informative STR data and appears useful in forensic casework and parentage testing.

Genetic analysis of eight population groups living in Taiwan using a 13 X-chromosomal STR loci multiplex system.

A 13 X-chromosomal short tandem repeat (STR) multiplex system (DXS6807, DXS8378, DSX9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7424, DXS101, GATA172D05, HPRTB, DXS8377, and DXS7423) was tested on 1,037 DNA samples from eight population groups currently living in Taiwan. Different distributions of the allelic frequencies in different populations were presented. DXS8377 and DXS101 were the two most polymorphic loci in these eight populations, whereas DXS7423 was the least informative marker in most of the populations studied. The genetic distances between the populations and the constructed phylogenetic tree revealed a long genetic distance between Asian and Caucasian populations as well as isolation of the Tao population. The phylogenetic tree grouped populations into clusters compatible with their ethnogeographic relationships. This 13 X-chromosomal short tandem repeat multiplex system offers a considerable number of polymorphic patterns in different populations. This system can be useful in forensic identification casework and ethnogeographic research.

IDH1 and IDH2 Mutations in Colorectal Cancers.

OBJECTIVES: To elucidate clinicopathologic and molecular characteristics of IDH1 and IDH2 (IDH1/2) mutations in colorectal cancers (CRCs). METHODS: We evaluated IDH1/2 mutations in 1,623 CRCs using a next-generation sequencing assay. RESULTS: IDH1/2 mutations, predominantly IDH1 p.R132C, were detected in 15 (0.9%) CRCs and in 5 (3.0%) of 167 BRAF p.V600E-mutated CRCs. Three IDH1/2-mutated CRCs were associated with inflammatory bowel disease. They were significantly associated with old age, mucinous or signet ring cell adenocarcinoma, and high-grade histomorphology. Concordance of variant allele frequency between IDH1/2 mutants and other trunk drivers in CRCs and presence of IDH1/2 mutation in the adenoma and early adenocarcinoma indicated IDH1/2 mutations could be trunk drivers suitable for targeted therapy. CONCLUSIONS: IDH1/2 mutations in CRCs were uncommon but enriched in BRAF p.V600E-mutated CRCs and perhaps colitis-associated CRCs. Further studies on IDH1/2-mutated CRCs are needed to clarify their clinicopathologic features and implications for targeted therapy.

Seventeen Y-chromosomal short tandem repeat haplotypes in seven groups of population living in Taiwan.

The analysis of Y-chromosome short tandem repeat (Y-STR) loci is a powerful tool in forensic casework. The aim of this study was to present the 17 Y-STR loci haplotype distributions of groups of population living in Taiwan and to demonstrate genetic distances between the groups as well as multidimensional scaling plot based on Y-STR genotype data. Five hundred and fifteen DNA samples from unrelated males of seven groups of population, including Taiwanese Han, two groups of indigenous Taiwanese of Taiwan Island, Tao, mainland Chinese, Filipinos, and a group of people with European, Near Eastern, or South Asian ancestry, were analyzed using a commercial kit that co-amplifies 17 Y-STRs. A total of 471 different haplotypes with 440 unique haplotypes were identified. The overall haplotype diversity was 0.9995 +/- 0.0002. High haplotype diversity was observed in six groups of population, except the Tao. These Y-STRs revealed a low discrimination capacity in the Tao population (36.84%), which should be considered in forensic practice. The multidimensional scaling plot of these seven groups of population constructed based on the genetic distances according to 17 Y-STR loci presented a clear patrilineal genetic substructure in the area. Partial Y-STRs profiling reduced the discrimination capacity in most groups of population and distorted the multidimensional scaling plot.