A novel MMUT splicing variant causing mild methylmalonic acidemia phenotype

Objectives

Methylmalonic acidemia (MMA) is a rare inborn genetic disorder that is characterized by increased levels of methylmalonic acid in blood plasma and urine. Isolated methylmalonic acidemia is one of the most common types of MMA and is caused by mutations in the gene encoding methyl-malonyl coenzyme A mutase (MMUT). In this study, we investigated the possible mechanisms underlying the symptoms of isolated MMA in a patient by molecular analysis.

Methods

PCR amplification and Sanger sequencing analysis was performed to identify variants in the MMUT gene in the proband and his family. Furthermore, minigene constructs were generated to validate the splicing defects in the MMUT gene variant identified in the proband.

Results

The 3-year-old patient was admitted to the hospital with symptoms of MMA, including fever, convulsions, and vomiting. He showed metabolic acidosis, high levels of methylmalonic acid in blood and urine, and normal blood homocysteine levels. Genetic analysis demonstrated that the patient was a compound heterozygous carrier of two variants in the MMUT gene: a missense c.278G > A variant that has already been reported in a patient with the severe mut⁰ phenotype; and a novel splice site variant c.2125-2A > G. RT-PCR analysis showed that, while the novel variant clearly alters splicing, a minor amount of a full-length transcript is generated, suggesting that a wild-type protein may be produced although at a lower quantitative level. The patient's condition improved after treatment with vitamin B12. Serious complications were not reported during follow-up at age 5.

Conclusions

We identified a novel splice site variant that partially disrupts normal splicing of the MMUT pre-mRNA. Production of a reduced amount of full-length transcript is responsible for the mild clinical phenotype observed in this patient. Functional studies have proven useful in exploring the genotype-phenotype association and in providing guidance for the genetic diagnosis of MMA.

Genetic Association of Lipids and Lipid-Lowering Drug Target Genes With Attention Deficit Hyperactivity Disorder

BACKGROUND

Lipid metabolism plays an essential role in nervous system development. Cholesterol deficiency leads to a variety of neurodevelopmental disorders, such as autism spectrum disorder and fragile X syndrome. There have been a lot of efforts to search for biological markers associated with and causal to ADHD, among which lipid is one possible etiological factor that is quite widely studied. We aimed to evaluate the causal relationship between lipids traits, lipid-lowering drugs, and attention deficit hyperactivity disorder (ADHD) outcomes using Mendelian randomization (MR) studies.

METHODS

We used summary data from genome-wide association studies to explore the causal relationships between circulating lipid-related traits and ADHD. Then, quantitative trait loci for the expression of lipid-lowering drug target genes and genetic variants associated with lipid traits were extracted. Summary-data-based MR and inverse-variance-weighted MR (IVW-MR) were used to investigate the correlation between the expression of these drug-target genes and ADHD.

RESULTS

After rigorous screening, 939 instrumental variables were finally included for univariable mendelian randomization analysis. However, there is no correlation between lipid profile and ADHD risk. Drug target analysis by IVW-MR method observed that APOB-mediated low-density lipoprotein cholesterol was associated with lower ADHD risk (odds ratio [OR] = 0.90, 95% confidence interval [CI] [0.84, 0.97]; p = .007), whereas LPL-mediated triglycerides levels were associated with a higher risk of ADHD (OR = 1.13, 95% CI [1.06, 1.21]; p < .001).

CONCLUSION

Our results suggest that APOB gene and LPL gene may be candidate drug target genes for the treatment of ADHD.

Metal-support interaction boosts the stability of Ni-based electrocatalysts for alkaline hydrogen oxidation

Ni-based hydrogen oxidation reaction (HOR) electrocatalysts are promising anode materials for the anion exchange membrane fuel cells (AEMFCs), but their application is hindered by their inherent instability for practical operations. Here, we report a TiO2 supported Ni4Mo (Ni4Mo/TiO2) catalyst that can effectively catalyze HOR in alkaline electrolyte with a mass activity of 10.1 ± 0.9 A g-1Ni and remain active even up to 1.2 V. The Ni4Mo/TiO2 anode AEMFC delivers a peak power density of 520 mW cm-2 and durability at 400 mA cm-2 for nearly 100 h. The origin for the enhanced activity and stability is attributed to the down-shifted d band center, caused by the efficient charge transfer from TiO2 to Ni. The modulated electronic structure weakens the binding strength of oxygen species, rendering a high stability. The Ni4Mo/TiO2 has achieved greatly improved stability both in half cell and single AEMFC tests, and made a step forward for feasibility of efficient and durable AEMFCs.

Interfacial Electron Engineering of PdSn-NbN/C for Highly Efficient Cleavage of the C-C Bonds in Alkaline Ethanol Electrooxidation

The splitting of the C-C bonds of ethanol remains a key issue to be addressed, despite tremendous efforts made over the past several decades. This study highlights the enhancement mechanism of inexpensive NbN-modified Pd1 Sn3 -NbN/C towards the C-C bonds cleavage for alkaline ethanol oxidation reaction (EOR). The optimal Pd1 Sn3 -NbN/C delivers a catalytic activity up to 43.5 times higher than that of commercial Pd/C and high carbonate selectivity (20.5%) toward alkaline EOR. Most impressively, the Pd1 Sn3 -NbN/C presents good durability even after 25 200 s of chronoamperometric testing. The enhanced catalytic performance is mainly due to the interfacial interaction between PdSn and NbN, demonstrated by multiple structural characterization results. In addition, in situ ATR-SEIRAS (Attenuated total reflection-surface enhanced infrared absorption spectroscopy) results suggest that NbN facilitates the C-C bonds cleavage towards the alkaline EOR, followed by the enhanced OH adsorption to promote the subsequent oxidation of C1 intermediates after doping Sn. DFT (density functional theory) calculations indicate that the activation barriers of the C-H bond cleavage in CH3 CH2 OH, CH3 CHOH, CH3 CHO, CH3 CO, CH2 CO, and the C-C bond cleavage in CH3 CO, CH2 CO, CHCO are evidently reduced and the removal of adsorbed CH3 CO and CO becomes easier on the PdSn-NbN/C catalyst surface.

A Pair of Compound Heterozygous IARS2 Variants Manifesting West Syndrome and Electrolyte Disorders in a Chinese Patient

Background  Aminoacyl-tRNA synthetases (ARSs) are evolutionarily conserved enzymes that ensure the accuracy of the translation process. Isoleucyl-tRNA synthetase 2 ( IARS2 ) gene is a type of ARS that encodes mitochondrial isoleucine-tRNA synthetase. Pathogenic variants in the IARS2 gene are associated with mitochondrial disease which involves several patients presenting broad clinical phenotypes. These clinical phenotypes include West syndrome, Leigh syndrome, and Cataract, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss, and skeletal dysplasia syndrome. Only 29 cases have been reported worldwide. The patient manifested recurrent convulsions, and specific clinical manifestations included electrolyte disorders and recurrent infections. Methods  Whole-exome sequencing was performed on the child with West syndrome. Three-dimensional structure reconstruction and thermodynamic stability prediction were performed to further analyze the relationship between variation and phenotype. Conclusion  This study further expands the clinical spectrum of IARS2 pathogenic variants. The case summaries help raise clinical awareness of IARS2 -associated disease and reduce misdiagnosis. Result  In this report, a 13-month-old girl was diagnosed with West syndrome and Leigh syndrome for 7 months. Compound heterozygous variants in the IARS2 gene (NM_018060.4), c.2450G>A (Arg817His) and copy number variation (NC_000001. 11: g. (220267549_220284289) del), were detected by WES. This study further expands the clinical spectrum of IARS2 pathogenic variants. The case summaries help raise clinical awareness of IARS2-associated disease and reduce misdiagnosis.

Functional Characterization of a Novel SLC4A4 Variant and Uniparental Isodisomy in Proximal Renal Tubular Acidosis Patient

SLC4A4 variants are the etiologies of inherited proximal renal tubular acidosis (pRTA), which results in metabolic acidosis, hypokalemia, glaucoma, band keratopathy, and cataract. This study aims to characterize SLC4A4 variant and uniparental isodisomy of chromosome 4 in a patient, and analyse the functional characterization of SLC4A4 variants. This study analyzed renal tubular acidosis disease genes by whole exome sequencing (WES). H3M2 algorithm was used to analyze the run of homozygosity region in chromosomal regions in trio-WES data. The pathogenicity analysis of variants was performed using bioinformatics tools. Additionally, protein stability was analyzed by cycloheximide chase assay. Whole-cell patch clamping was used to examine the electrophysiological properties of NBCe1-A. A novel homozygous SLC4A4 variant was identified in the patient: a missense variant c.496C > T, p. Arg166Trp (NM_003759.4). But the father was heterozygous variant carrier, and the mother did not detect the variant. The H3M2 and UPDio algorithm revealed paternal uniparental isodisomy on chromosome 4 in the patient. SIFT, Poly Phen-2, FATHMM and Mutant Taster showed that the variant might be pathogenic. The tertiary structure analysis showed that the variant could cause structural damage to NBCe1 protein. Foldx results showed that the protein stability of the variant was slightly reduced. Cycloheximide chase assay demonstrated that the variant affects protein stability. The result of electrophysiological studies showed that the variant altered Na+/HCO3- cotransport activity of protein. In conclusion, the study is the first to report a pRTA patient with Arg166Trp variant with UPiD (4) pat and analyze the function of Arg166Trp variant.

Beware of missed diagnosis in patients with multiple genetic diseases: a case report

Background

Duchenne muscular dystrophy (DMD) is an X-linked recessive inherited disorder caused by the absence of the Dystrophin protein. Cerebral cavernous malformations (CCMs) are the most common vascular abnormalities in the central nervous system caused by the absence of the products of the CCM genes. Most CCMs cases reported occurring in a sporadic form are often asymptomatic.

Case presentation

We report a rare case of a 7-year-old Chinese boy with a co-existing DMD and sporadic CCMs. We found classic clinical features of DMD and non-specific pathological changes in his brain. We made the definitive diagnosis based on the results of whole-exome sequencing (WES), a repeat from exon 3 to exon 9 of the DMD inherited from his mother, and a de novo heterozygote nonsense mutation C.418G > T of the PDCD10 exon 6.

Conclusion

We should take care to avoid missed diagnoses in patients with multiple genetic disorders.

Identification of a Novel Deep Intronic Variant by Whole Genome Sequencing Combined With RNA Sequencing in a Chinese Patient With Menkes Disease

Background: Menkes disease (MD) is a rare X-linked connective tissue disorder of copper metabolism caused by pathogenic variant(s) in ATP7A gene. The aim of the present study is to determine the clinical characteristics and molecular basis of one patient with MD.

Methods: One 10-month-old Chinese boy who met the clinical manifestations of MD was enrolled in this study. Whole genome sequencing (WGS) was performed in the patient in order to identify the variant(s), followed by Sanger sequencing. RNA sequencing (RNA-seq) from whole blood was subsequently applied to assess the effect of variant on transcription levels, and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed for further validation. In addition, X chromosome inactivation (XCI) status of the patient’s mother at the DNA level was measured by capillary electrophoresis.

Results: The patient suffered from intermittent convulsions for more than 6 months, with psychomoto retardation and neurodegenerations. The patient also had curly hair, hypopigmented skin, cutis laxa, decreased muscle strength and hypotonia. MRI showed the intracranial arteries were tortuous with some “spiral” changes. The patient’s serum ceruloplasmin level was low. WGS revealed one novel hemizygous variant, c.2627-501C > T (NM_000,052.7), located in the deep intronic sequence of ATP7A gene. Sanger sequencing confirmed that the variant was inherited from his mother. RNA-seq confirmed the variant itself, and identified a pseudo-exon inserted between exons 12 and 13 in mRNA of ATP7A. The sequencing results of RT-PCR from the patient confirmed this finding, while neither of his parents detected aberrant splicing. The Capillary electrophoresis results showed that the patient’s mother had a skewed XCI.

Conclusion: Our finding of the variant enlarges the variant spectrum in the ATP7A gene. This is a novel deep intronic variant which leads to the activation of a pseudo-exons in the ATP7A gene, and it demonstrates the usefulness of WGS combined with RNA-seq, in terms of revealing disease-causing variants in non-coding regions. Furthermore, the fact that the deep intronic variants cause disease by the activation of pseudo-exon inclusion indicates that in MD this might be an important mechanism.

Case report: Altered pre-mRNA splicing caused by intronic variant c.1499 + 1G > A in the SLC4A4 gene

Proximal renal tubular acidosis (pRTA) with ocular abnormalities is an autosomal recessive disease caused by variants in the Solute Carrier Family 4 Member 4 (SLC4A4) gene. Patients present with metabolic acidosis and low plasma bicarbonate concentration (3∼17 mmol/L). In addition, they are often accompanied by ocular abnormalities, intellectual disability, and growth retardation. The patient underwent whole exome sequencing (WES) and bioinformatics analysis of variant pathogenicity in this study. Then, a minigene assay was conducted to analyze the splicing site variant further. Compound heterozygous variants in the SLC4A4 gene (NM_003759.3), c.145C > T (p.Arg49*) and c.1499 + 1G > A, were detected by WES. The minigene assay showed an mRNA splicing aberration caused by the c.1499 + 1G > A variant. Compared with the wild type, the mutant type caused 4-base insertion between exons 10 and 11 of SLC4A4 after expression in HEK293 cells. In conclusion, the c.1499 + 1G > A variant in the SLC4A4 gene may be one of the genetic causes in the patient. Moreover, our study provides the foundation for future gene therapy of such pathogenic variants.

Case Report: A Case of β-Ureidopropionase Deficiency Complicated With MELAS Syndrome Caused by UPB1 Variant and Mitochondrial Gene Variant

BACKGROUND

β-Ureidopropionase deficiency is a rare autosomal recessive disease affecting the last step of pyrimidine degradation. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a rare inherited disorder caused by genetic defects in mitochondrial DNA.

CASE PRESENTATION

One 8-year-old boy presented with dizziness, vomiting, and convulsions. The gas chromatography-mass spectrometry results suggested β-ureidopropionase deficiency. The whole-exome sequencing results revealed homozygous missense variant c.977G>A (p.R326Q) in UPB1. However, the patient presented with persistent hyperlactacidemia and metabolic acidosis, which did not correspond to the classic features of β-ureidopropionase deficiency. Combined with the manifestations of developmental delay, poor academic performance, and poor sports stamina, whole-mitochondrial-genome sequencing was performed. The results exhibited the variant m.3243A>G of MT-TL1 gene. The level of heterogeneity was 65% in the patient and 17.8% in his mother. Eventually, the final diagnosis of β-ureidopropionase deficiency combined with MELAS syndrome was made.

CONCLUSION

The report about β-ureidopropionase deficiency caused by a nuclear gene variant and MELAS syndrome caused by a mitochondrial gene variant coexisting in the same patient enriches the clinical study of these two rare diseases.

Diagnostic Value of the Fimbriae Distribution Pattern in Localization of Urinary Tract Infection

Urinary tract infections (UTIs) are one of the most common infectious diseases. UTIs are mainly caused by uropathogenic Escherichia coli (UPEC), and are either upper or lower according to the infection site. Fimbriae are necessary for UPEC to adhere to the host uroepithelium, and are abundant and diverse in UPEC strains. Although great progress has been made in determining the roles of different types of fimbriae in UPEC colonization, the contributions of multiple fimbriae to site-specific attachment also need to be considered. Therefore, the distribution patterns of 22 fimbrial genes in 90 UPEC strains from patients diagnosed with upper or lower UTIs were analyzed using PCR. The distribution patterns correlated with the infection sites, an XGBoost model with a mean accuracy of 83.33% and a mean area under the curve (AUC) of the receiver operating characteristic (ROC) of 0.92 demonstrated that fimbrial gene distribution patterns could predict the localization of upper and lower UTIs.

Age distribution of human papillomavirus infection and neutralizing antibodies in healthy Chinese women aged 18-45 years enrolled in a clinical trial

OBJECTIVES

Data from clinical trials of human papillomavirus (HPV) vaccines showed that women naïve (negative for both type-specific antibodies and DNA) to vaccine types would derive benefit from vaccination; therefore, an understanding of the proportion of naïve women in different age groups is important for developing HPV vaccination strategies.

METHODS

From November 2012 to April 2013, a total of 7372 healthy women aged 18-45 years were recruited in five provinces in China. Cervical specimens and serum samples were collected for each woman at entry. Cervical specimens were first tested by the HPV DNA enzyme immunoassay method; if positive, the specimens were then tested by reverse hybridization line probe assay and HPV-16 and HPV-18 specific polymerase chain reactions. Neutralizing antibodies against HPV-16 or HPV-18 were tested with a pseudovirion-based neutralization assay.

RESULTS

The overall prevalence of high-risk HPV DNA was 14.8% (1088/7367, 95% CI 14.0-15.6), and the seroprevalence of neutralizing antibodies against HPV-16 and HPV-18 was 12.6% (925/7367) and 4.9% (364/7367), respectively. In younger women (18-26 years) and middle-aged women (27-45 years), 83.8% (3116/3719) and 81.4% (2968/3648) were naïve to both HPV-16 and HPV-18 (both neutralizing antibodies and DNA were negative), respectively. In addition, 98.5% (3664/3719) and 98.0% (3575/3648) of the younger or middle-aged women were naïve to at least one HPV type (HPV-16 or HPV-18).

DISCUSSION

This study revealed that the majority of Chinese women aged 18-26 years and 27-45 years were naïve to both HPV-16 and HPV-18 and would thus derive full benefit from bivalent HPV vaccination.

Incidence and mortality of nasopharyngeal carcinoma: interim analysis of a cluster randomized controlled screening trial (PRO-NPC-001) in southern China

BACKGROUND

Previous mass screening studies have shown that IgA antibodies against Epstein-Barr Virus (EBV) can facilitate early detection of nasopharyngeal carcinoma (NPC), but the impact of EBV-antibody screening for NPC-specific mortality remains unknown.

PATIENTS AND METHODS

A prospective, cluster randomized, controlled trial for NPC screening (PRO-NPC-001) was conducted in 3 selected towns of Zhongshan City and 13 selected towns of Sihui City in southern China beginning in 2008. Serum samples of the screening group were tested for two previously selected anti-EBV antibodies. Subjects with serological medium risk were subsequently retested annually for 3 years, and those with serological high risk were referred to otorhinolaryngologists for diagnostic check-up. An interim analysis was carried out to evaluate the primary end points of the NPC-specific mortality and the early diagnostic rate, and the secondary end point of the NPC incidence, through linkage with the database of Zhongshan City.

RESULTS

Among 70 296 total subjects, 29 413 screened participants (41.8% of the total subjects) in the screening group and 50 636 in the control group, 153 (43.3 per 100 000 person-year), 62 (55.3 per 100 000 person-year) and 99 (33.1 per 100 000 person-year) NPC cases were identified. The early diagnostic rates of NPC were significantly higher in the participants (79.0%, P < 0.0001) and the screening group (45.9%, P < 0.0001) compared with the control group (20.6%). Although no differences were found between NPC-specific mortality of the screening group and the control group [relative risk (RR)= 0.82, 95% confidence interval (CI) 0.37-1.79], lower NPC-specific mortality was noticed among participants from the screening group versus the control group (RR = 0.22, 95% CI 0.09-0.49).

CONCLUSION

IgA antibodies against EBV can identify high-risk population and was effective in screening for early asymptomatic NPC. Although the mortality reduction was not significant in the primary end point, we noted encouraging evidence of a mortality reduction in screening participants in this interim analysis.

CLINICAL TRIAL NUMBER

NCT00941538.

Hydrogen Evolution and Oxidation: Mechanistic Studies and Material Advances

Electrochemical energy storage and conversion through hydrogen is essential for a clean and sustainable energy system. Highly efficient hydrogen electrocatalysts play a key role in the electrochemical transformation reactions. A comprehensive understanding of the hydrogen reaction kinetics and mechanisms is critical for the catalyst design and development. Especially pH-dependent hydrogen evolution and oxidation reaction (HER/HOR) kinetics receives increasing interest, and understanding its origin adds new knowledge to fundamental hydrogen electrocatalysis. Here, a detailed description of kinetic analysis and reaction mechanisms for HER/HOR, and a brief summary about recent development of highly efficient and cost-effective hydrogen electrocatalysts are presented. Lastly, recent advances in the fundamental understanding of pH-dependent hydrogen electrocatalysis are discussed.

Extracellular matrix protein 1 promotes cell metastasis and glucose metabolism by inducing integrin β4/FAK/SOX2/HIF-1α signaling pathway in gastric cancer

Extracellular matrix protein 1 (ECM1) is related to strong invasiveness and poor prognosis in major malignancies, but the underlying mechanism remains unknown. Here we aimed to elucidate the function of ECM1 on cell metastasis and glucose metabolism in gastric cancer (GC). The level of ECM1 in sera and tissues of patient with GC were positively correlated with tumor invasion and recurrence. Genetic manipulation of ECM1 expression affected cell metastasis and glucose metabolism in GC cell lines. Enhanced ECM1 expression facilitated gene expression levels associated with epithelial-mesenchymal transition (EMT) and glucose metabolism. Interestingly, our results indicated that ECM1 directly interacted with integrin β4 (ITGB4) and activated ITGB4/focal adhesion kinase (FAK)/glycogen synthase kinase 3β signaling pathway, which further induced the expression of transcription factor SOX2. Aberrant expression of SOX2 altered gene expression of EMT factors and glucose metabolism enzymes. Furthermore, SOX2 enhanced hypoxia-inducible factor α (HIF-1α) promoter activity to regulate glucose metabolism. The micro-positron emission tomography/computed tomography imaging of xenograft model showed that ECM1 substantially increased ¹⁸F-fluorodeoxyglucose uptake in xenograft tumors. Using in vivo mouse tail vein injection experiments, ECM1 was also found to increase in lung surface metastasis. These findings provide evidence that ECM1 regulates GC cell metastasis and glucose metabolism by inducing ITGB4/FAK/SOX2/HIF-1α signal pathway and have important implications for the development of therapeutic target to prevent tumor metastasis and recurrence.

Neurobehavioral Functions, Serum Prolactin and Plasma Renin Activity of Manganese-Exposed Workers

Objective of this study was to assess effects of manganese (Mn) exposure on 56 workers employed in a Mn welding workshop of a machine building factory in Taiyuan (Shanxi Province, P.R. China) for a mean period of 16.1 years. The mean air Mn level in the workshop was 138.4 μg/m3. Neurobehavioral Core Test Battery (NCTB), including the Profile of Mood States (POMS), was performed. Blood pressure (BP) increase following immediate stand-up (BP-IS), serum prolactin (PRL) and plasma renin activity (PRA) in supine position were also determined. Most of the NCTB scores of the Mn-exposed workers were lower than those of the controls, while the POMS scores were higher, indicating a Mn-induced impairment of neurophysiological functions and a deflection of mood towards negative emotion states. PRL values of the Mn-exposed workers were higher than those of the controls. BP-IS of Mn-exposed workers was significantly lower than that of the controls. PRA of the same workers was augmented more than 200 %. In the Mn-exposed workers, the higher PRL values are possibly due to a reduced inhibitory effect on pituitary lactotrope cells by the tubero-infundibular dopamine system; the decreased BP-IS was referred to imbalance between the sympathetic and parasympathetic activities, whereas the higher basal PRA was thought to depend on neuroendocrine changes (including increased central sympathetic tone) and/or on a direct effect of Mn on renal juxta-glomerular cells. On the whole, this study demonstrates that occupational Mn exposure is responsible for neurobehavioral changes coexisting with alterations of neuroendocrine and humoral systems.

Universal dependence of hydrogen oxidation and evolution reaction activity of platinum-group metals on pH and hydrogen binding energy

Understanding how pH affects the activity of hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is key to developing active, stable, and affordable HOR/HER catalysts for hydroxide exchange membrane fuel cells and electrolyzers. A common linear correlation between hydrogen binding energy (HBE) and pH is observed for four supported platinum-group metal catalysts (Pt/C, Ir/C, Pd/C, and Rh/C) over a broad pH range (0 to 13), suggesting that the pH dependence of HBE is metal-independent. A universal correlation between exchange current density and HBE is also observed on the four metals, indicating that they may share the same elementary steps and rate-determining steps and that the HBE is the dominant descriptor for HOR/HER activities. The onset potential of CO stripping on the four metals decreases with pH, indicating a stronger OH adsorption, which provides evidence against the promoting effect of adsorbed OH on HOR/HER.

Can tumor regression grade influence survival outcome in ypT3 rectal cancer?

PURPOSE

Locally advanced rectal cancer (LARC) patients achieving ypT3 status following neoadjuvant chemoradiation are considered to have poor response with minimal downstaging. However, residual cancer cell amounts vary in the subserosa/perirectal fat. Tumor regression grading (TRG) is an evaluation method based on the proportion of fibrosis and residual cancer cells. The aim of this study is to assess the influence of TRG in ypT3 rectal cancer patients who received neoadjuvant chemoradiation.

METHODS

We retrospectively reviewed 325 LARC patients who received neoadjuvant chemoradiation and surgery. TRG scores were recorded by two independent pathologists. Among these patients, 143 were staged as ypT3. We analyzed TRG and other clinicopathological factors and their relationship with survival outcome including overall survival (OS) and disease-free survival (DFS).

RESULTS

Among 143 ypT3 patients, 44 (30.8 %) were TRG1, 84 (58.7 %) were TRG2 and 15 (10.5 %) were TRG3. Seventy-nine (55.3 %) of these patients had metastatic lymph nodes. In univariate analysis, TRG was not associated with DFS (TRG2 vs TRG1, P = 0.852; TRG3 vs TRG1, P = 0.593) or OS (TRG2 vs TRG1, P = 0.977; TRG3 vs TRG1, P = 0.665). Palliative surgery (HR 3.845; 95 % CI 1.670-8.857; P = 0.002) and metastatic lymph nodes after surgery (HR 5.894; 95 % CI 1.142-3.48; P = 0.015) were significantly associated with decreased DFS, while palliative surgery was the only factor associated with worse OS (HR 6.011; 95 % CI 2.150-16.810; P = 0.001). Palliative surgery (HR 3.923; 95 % CI 1.696-9.073; P = 0.001) and metastatic lymph nodes (HR 2.011; 95 % CI 1.152-3.512; P = 0.014) also showed prognostic significance for DFS in multivariate analysis.

CONCLUSIONS

Residual cancer cells evaluated by TRG score after neoadjuvant chemoradiation do not influence survival outcome in ypT3 rectal cancer patients. However, lymph node status is a significant prognostic factor in ypT3 patients.

A simplified genomic DNA extraction protocol for pre-germination genotyping in rice

Genotyping is a critical step for molecular marker-assisted selection in rice. Rice genomic DNA samples for genotyping are typically isolated from living tissues such as seedlings. This requires the germination of all candidate seeds and extraction of DNA from the seedlings. Currently, an ideal individual is selected from a very large number of plants, which is time- and labor-consuming, requiring several transplantations of materials and sampling processes. In this study, we developed a simplified genomic DNA extraction protocol in rice by using amylase to treat half-seeds. The yields of genomic DNA from a half-seed of Indica and Japonica rice were greater than 203.8 ± 32.5 and 143.2 ± 25.5 ng, respectively, and the 260/280 nm absorbance ratio was 1.75-2.10. The DNA was confirmed to be sufficient for polymerase chain reaction amplification and can be used in a marker-assisted selection program.

Astrocytes regulate α-secretase-cleaved soluble amyloid precursor protein secretion in neuronal cells: Involvement of group IIA secretory phospholipase A2

Astrocytes are major supportive cells in brains with important functions including providing nutrients and regulating neuronal activities. In this study, we demonstrated that astrocytes regulate amyloid precursor protein (APP) processing in neuronal cells through secretion of group IIA secretory phospholipase A2 (sPLA2-IIA). When astrocytic cells (DITNC) were mildly stimulated with the pro-inflammatory cytokines, such as TNF α and IL-1β, sPLA2-IIA was secreted into the medium. When conditioned medium containing sPLA2-IIA was applied to human neuroblastoma (SH-SY5Y) cells, there was an increase in both cell membrane fluidity and secretion of α-secretase-cleaved soluble amyloid precursor protein (sAPPα). These changes were abrogated by KH064, a selective inhibitor of sPLA2-IIA. In addition, exposing SH-SY5Y cells to recombinant human sPLA2-IIA also increased membrane fluidity, accumulation of APP at the cell surface, and secretion of sAPPα, but without altering total expressions of APP, α-secretases and β-site APP cleaving enzyme (BACE1). Taken together, our results provide novel information regarding a functional role of sPLA2-IIA in astrocytes for regulating APP processing in neuronal cells.

A meta-analysis of pemetrexed-based doublet compared with pemetrexed alone for the second-line treatment of advanced non-small-cell lung cancer

PURPOSE

This meta-analysis investigated pemetrexed-based doublet compared with pemetrexed alone as second-line therapy for patients with advanced non-small cell lung cancer.

METHODS

Randomized controlled trials which compared pemetrexed-based doublet with single-agent pemetrexed in patients as second-line treatment of advanced non-small cell lung cancer were searched. Overall survival (OS) was the primary end point, while secondary end points included progression-free survival, overall response rate, 1-year survival rate, and grade 3 or 4 toxicity.

RESULTS

Four eligible randomized clinical trials including 1,084 patients were selected. Meta-analysis demonstrated that pemetrexed-based doublet arm significantly improved the overall response rate (OR=2.70, 95% CI: 1.76-4.15, p=0.000), compared with docetaxel alone group, while there were no significant differences in overall survival (HR=0.88, 95% CI: 0.74-1.04, p=0.132), progression-free survival (HR=0.91, 95% CI: 0.73-1.15, p=0.443), and 1-year survival rate (OR=1.43, 95% CI: 0.85-2.40, p=0.178) between the two arms. However, there were more frequencies of grade 3-4 leucopenia (OR=2.86, 95% CI: 1.32-6.20, p=0.008), neutropenia (OR=2.69, 95% CI: 1.55-4.68, p=0.000) and thrombocytopenia (OR=6.92, 95% CI: 2.51-19.07, p=0.000) in pemetrexed-based doublet group. Grade 3-4 anemia (OR=0.62, 95% CI: 0.33-1.18, p=0.144) and fatigue (OR=1.15, 95% CI: 0.73-1.79, p=0.550) had equivalent incidences in the two groups.

CONCLUSIONS

This is the first meta-analysis to compare pemetrexed-based doublet with single-agent pemetrexed in second-line therapy of non-small cell lung cancer. Our meta-analysis suggested that pemetrexed combination chemotherapy was not superior to single-agent arm and was not recommended as the second-line chemotherapy for patients with non-small cell lung cancer (Tab. 2, Fig. 6, Ref. 20).

Clinical and experimental observations of peripheral blood leukocytes and nucleated bone marrow cells after local irradiation

AIM

Aim of the study was to observe the impact of bone marrow damage induced by local irradiation on leukopenia.

METHODS

For the human study, five cancer patients received local radiation therapy. Bone marrow aspiration was conducted to measure nucleated cell count and 99mTc-Sc sulfur colloid ECT imaging was carried out to examine bone marrow function. For the animal study, fifty New Zealand white rabbits were divided into 3 groups: non-irradiated control group (N.=10), abdomen irradiation group (irradiation area did not cover bone marrow) (N.=20), chest irradiation group (irradiation area covered bone marrow) (N.=20). Nucleated cell counts were taken after confirming onset of leukopenia.

RESULTS

Bone marrow of five patients proliferated normally. ECT imaging showed no abnormality in the pattern of red bone marrow distribution. Hematopoietic function was mildly active.

CONCLUSION

Suppressed myeloproliferative function does not fully account for irradiation-induced leukopenia.

Tumour diameter is a predictor of mesorectal and mesenteric lymph node metastases in anorectal melanoma

AIM

Anorectal melanoma is a rare neoplasm with poor prognosis. The aim of this study was to investigate what clinicopathological factors predict lymph node metastases and to investigate their association with survival.

METHOD

Patients undergoing surgery with curative intent for primary anorectal melanoma in Fudan University Shanghai Cancer Center between 1989 and 2011 were studied retrospectively. The associations between clinicopathological factors and lymph node metastases and prognosis were determined.

RESULTS

Forty-three patients underwent a potentially curative resection with a median follow-up of 20 months; the 5-year overall survival rate was 29.6% with median overall survival of 28 months. Tumour diameter > 3 cm was associated with mesorectal and mesenteric lymph node metastases (P = 0.013). Perineural invasion (hazard ratio 5.683; 95% CI 1.978-16.328; P = 0.001) was the only factor that independently predicted survival.

CONCLUSION

Tumour diameter was associated with mesorectal and mesenteric lymph node metastases; therefore, wide local excision may not be appropriate for surgery with curative intent for patients with a tumour diameter ≥ 3 cm. Perineural invasion was an important prognostic factor for anorectal melanoma.

Intraoperative electron beam radiotherapy for primary treatment of stage IIB cervical cancer: a retrospective study

OBJECTIVE

A retrospective study to evaluate intraoperative electron beam radiotherapy (IOERT) as a primary treatment modality for stage IIB cervical squamous cell carcinoma.

METHODS

Patients underwent treatment with IOERT (n = 78) or radical radiotherapy (RT; n = 89). Patients in the IOERT group received 20 Gy external beam radiotherapy (EBRT) in 10 fractions, intracavitary brachytherapy (7-14 Gy, in patients with tumours ≥ 4 cm in diameter) and simple hysterectomy/selective lymphadenectomy with 18 - 20 Gy IOERT. Patients in the RT group received 50 Gy EBRT in 25 fractions followed by intracavitary brachytherapy (35-40 Gy).

RESULTS

Median duration of follow-up was 92 months. IOERT resulted in significantly better 5- and 10-year overall survival, disease-free survival and local control rates, as well as fewer rectal and bladder complications, compared with RT.

CONCLUSION

IOERT is an effective primary treatment for stage IIB cervical squamous cell carcinoma.

Prognostic significance of apical lymph node metastasis in patients with node-positive rectal cancer

AIM

The aim of this study was to assess the effect of apical lymph node (APN) metastasis in predicting prognosis in curatively treated node-positive rectal cancer. We also investigated the relationship between APN metastasis and the total number of metastatic lymph nodes.

METHOD

A retrospective study was performed of 510 curatively treated patients with node-positive rectal cancer. Clinicopathological variables, including APN status, were assessed in univariate and multivariate analyses. The prognostic significance of APN status in predicting patient outcomes and the relationship between APN status and American Joint Committee on Cancer (AJCC) N stage were analysed.

RESULTS

At a median follow up of 47 months, the 5-year local recurrence (LR) rate, the disease-free survival (DFS) rate and the overall survival (OS) rate were 18.3%, 55.5% and 58.8%, respectively. The 5-year OS rate was 69.6% for patients with no metastasis in APNs (APN(-)) and 40.8% for patients with metastasis in APNs (APN(+)). DFS and OS for patients with undetermined APN status were between those for APN(-) and APN(+). Subgroup analysis gave a 5-year OS rate of 48.7% in Stage N1 patients with APN(+) and 58.8% for Stage N2 patients with APN(-) (P = 0.0004).

CONCLUSION

APN metastasis is an important prognostic factor in node-positive rectal cancer, which provides additional survival-related prognostic classification irrespective of N stage. As the APN is usually outside the radiation field, in the era of multidisciplinary treatment its assessment should be incorporated into prognostic evaluation of rectal cancer.