The role of deep learning-based survival model in improving survival prediction of patients with glioblastoma.

This retrospective study has been conducted to validate the performance of deep learning-based survival models in glioblastoma (GBM) patients alongside the Cox proportional hazards model (CoxPH) and the random survival forest (RSF). Furthermore, the effect of hyperparameters optimization methods on improving the prediction accuracy of deep learning-based survival models was investigated. Of the 305 cases, 260 GBM patients were included in our analysis based on the following criteria: demographic information (i.e., age, Karnofsky performance score, gender, and race), tumor characteristic (i.e., laterality and location), details of post-surgical treatment (i.e., time to initiate concurrent chemoradiation therapy, standard treatment, and radiotherapy techniques), and last follow-up time as well as the molecular markers (i.e., O-6-methylguanine methyltransferase and isocitrate dehydrogenase 1 status). Experimental results have demonstrated that age (Elderly > 65: hazard ratio [HR] = 1.63; 95% confidence interval [CI]: 1.213-2.18; p value = 0.001) and tumors located at multiple lobes ([HR] = 1.75; 95% [CI]: 1.177-2.61; p value = 0.006) were associated with poorer prognosis. In contrast, age (young < 40: [HR] = 0.57; 95% [CI]: 0.343-0.96; p value = 0.034) and type of radiotherapy (others include stereotactic and brachytherapy: [HR] = 0.5; 95%[CI]: 0.266-0.95; p value = 0.035) were significantly related to better prognosis. Furthermore, the proposed deep learning-based survival model (concordance index [c-index] = 0.823 configured by Bayesian hyperparameter optimization), outperformed the RSF (c-index = 0.728), and the CoxPH model (c-index = 0.713) in the training dataset. Our results show the ability of deep learning in learning a complex association of risk factors. Moreover, the remarkable performance of the deep-learning-based survival model could be promising to support decision-making systems in personalized medicine for patients with GBM.

Occupational exposure to metal-rich particulate matter modifies the expression of repair genes in foundry workers.

Foundry workers are exposed to numerous occupational health hazards, which may result in increased risk of cancer, respiratory disease, and other diseases. Oxidative stress is known to be involved in the pathogenesis of such diseases. The present study aimed to investigate the association between multiple occupational exposures in foundry workers and expression of deoxyribonucleic acid (DNA) repair genes as a biomarker of oxidative DNA damage. The study sample comprised 17 foundry workers and 27 matched control subjects. Expression of 8-oxoguanine DNA glycosylase-1 (OGG1), inosine triphosphate pyrophosphate (ITPA), and MutT homolog 1 (MTH1) in peripheral blood was examined using the real-time polymerase chain reaction method. Air sampling to determine exposure to metal-rich particulate matter and measurement of extremely low-frequency electromagnetic fields (ELF-EMFs) were conducted according to the National Institute for Occupational Safety and Health standard methods. Personal air sampling revealed that occupational exposure to particulate matter exceeded the threshold limit values (TLVs) in 76% of the workstations, whereas ELF-EMF exposure appeared to be lower than the TLV. ITPA was significantly upregulated in foundry workers compared with control subjects, whereas no significant difference was observed for OGG1 and MTH1. Moreover, ITPA was strongly and positively correlated with the concentration of metal-rich particulate matter in foundry workers. No significant correlation was found between ELF-EMF exposure and expression of DNA repair genes. DNA repair gene expression may be a sensitive biomarker for occupational exposures, which suggests an involvement of oxidative stress in metal-induced toxicity. Further studies are needed to determine the role of DNA repair gene expression in response to occupational/environmental hazards.

Proteomic analysis of infected primary human leucocytes revealed PSTK as potential treatment-monitoring marker for active and latent tuberculosis.

Markers for monitoring clearance of Mycobacterium tuberculosis (Mtb) infection during anti-TB drug treatment could facilitate management of tuberculosis (TB) treatment, but are lacking. We aimed to screen for Mtb clearance markers from in-vitro-infected leucocytes and to evaluate these markers in followed-up active TB (ATB) patients and latent TB (LTBI) cases after anti-TB drug treatment. Extracellular proteins from primary leucocytes infected with each of the Mtb lineages (East-Asian, Indo-Oceanic, Euro-American and the laboratory strain H37Rv) were screened as possible clearance markers. Leucocytes infected with Staphylococcus aureus acted as controls. The proteomic analysis was performed using GeLC-MS/MS. Several quantitative and qualitative candidate clearance markers were found. These proteins were suppressed during the infection stage of all Mtb lineages and re-expressed after bacillary clearance. PSTK, FKBP8 and MGMT were common clearance markers among the four Mtb lineages in our model. Only PSTK was a potential clearance marker based on western blot validation analysis from culture supernatants. The PSTK marker was further validated with western blot analysis using serum samples (n = 6) from ATB patients and LTBI cases during anti-TB drug treatment, and from healthy controls (n = 3). Time-dependent increase of PSTK was found both in ATB and LTBI patients during the course of anti-TB drug treatment, but not in healthy controls. We have demonstrated that PSTK is a potential treatment-monitoring marker for active and latent TB.

Haplotypes of HTRA1 rs1120638, TIMP3 rs9621532, VEGFA rs833068, CFI rs10033900, ERCC6 rs3793784, and KCTD10 rs56209061 Gene Polymorphisms in Age-Related Macular Degeneration.

BACKGROUND: To determine the impact of HTRA1 rs1120638, TIMP3 rs9621532, VEGFA rs833068, CFI rs10033900, ERCC6 rs3793784, and KCTD10 rs56209061 genotypes on the development of age-related macular degeneration (AMD) in the Lithuanian population. METHODS: A total of 916 subjects were examined: 309 patients with early AMD, 301 patients with exudative AMD, and 306 healthy controls. The genotyping of HTRA1 rs11200638, TIMP3 rs9621532, VEGFA rs833068, CFI rs10033900, ERCC6 rs3793784, and KCTD10 rs56209061 was carried out using the RT-PCR method. RESULTS: Our study showed that single-nucleotide polymorphisms rs3793784 and rs11200638 were associated with increased odds of early and exudative AMD, and the variant in KCTD10 (rs56209061) was found to be associated with decreased odds of early and exudative AMD development after adjustments for age and gender in early AMD analysis and after adjustments only for age in exudative AMD. The haplotype containing two minor alleles C-A and the G-A haplotype in rs3793784-rs11200638 were statistically significantly associated with an increased risk of exudative AMD development after adjustment for age, while the G-G haplotype showed a protective role against early and exudative AMD and the haplotype C-G in rs3793784-rs11200638 was associated with a decreased risk only of exudative AMD development. CONCLUSIONS: Our study identified two markers, rs11200638 and rs3793784, as risk factors for early and exudative AMD, and one marker, rs56209061, as a protective factor for early and exudative AMD development. The haplotypes constructed of rs3793784-rs11200638 were found to be associated with AMD development, as well.

Molecular and Kinetic Analyses of Circulating Tumor Cells as Predictive Markers of Treatment Response in Locally Advanced Rectal Cancer Patients.

Neoadjuvant chemoradiation (NCRT) followed by total mesorectal excision is the standard treatment for locally advanced rectal cancer (LARC). To justify a non-surgical approach, identification of pathologic complete response (pCR) is required. Analysis of circulating tumor cells (CTCs) can be used to evaluate pCR. We hypothesize that monitoring of thymidylate synthase (TYMS) and excision repair protein, RAD23 homolog B (RAD23B), can be used to predict resistance to chemotherapy/radiotherapy. Therefore, the aims of this study were to analyze CTCs from patients with LARC who underwent NCRT plus surgery for expression of TYMS/RAD23B and to evaluate their predictive value. Blood samples from 30 patients were collected prior to NCRT (S1) and prior to surgery (S2). CTCs were isolated and quantified by ISET®, proteins were analyzed by immunocytochemistry, and TYMS mRNA was detected by chromogenic in situ hybridization. CTC counts decreased between S1 and S2 in patients exhibiting pCR (p = 0.02) or partial response (p = 0.01). Regarding protein expression, TYMS was absent in 100% of CTCs from patients with pCR (p = 0.001) yet was expressed in 83% of non-responders at S2 (p < 0.001). Meanwhile, RAD23B was expressed in CTCs from 75% of non-responders at S1 (p = 0.01) and in 100% of non-responders at S2 (p = 0.001). Surprisingly, 100% of non-responders expressed TYMS mRNA at both timepoints (p = 0.001). In addition, TYMS/RAD23B was not detected in the CTCs of patients exhibiting pCR (p = 0.001). We found 83.3% of sensitivity for TYMS mRNA at S1 (p = 0.001) and 100% for TYMS (p = 0.064) and RAD23B (p = 0.01) protein expression at S2. Thus, TYMS mRNA and/or TYMS/RAD23B expression in CTCs, as well as CTC kinetics, have the potential to predict non-response to NCRT and avoid unnecessary radical surgery for LARC patients with pCR.

Radioprotective effect of melatonin on expression of Cdkn1a and Rad50 genes in rat peripheral blood.

OBJECTIVE: Ionizing radiation is a critical threat to biomolecules, especially DNA. Various combinatorial compounds have been studied to protect this biomolecule. Melatonin has been reported as a direct and indirect free radical scavenger, but in this study, we explored the effect of melatonin on assisting in DNA repair by expression of Cdkn1a and Rad50; both of these genes are involved in DNA repair signaling, induced by radiation in rat peripheral blood. MATERIALS AND METHODS: Rats were irradiated with single whole-body linear accelerator X-ray radiation doses of 2 and 8 Gy with or without melatonin (100 mg/kg body weight) pretreatments. The rats were randomly divided into nine groups and given an intraperitoneal injection of melatonin or the same volume of vehicle alone 1 h before radiation. Blood samples were taken 8, 24, and 48 h postradiation to measure gene expression of Cdkn1a and Rad50 using quantitative reverse transcription polymerase chain reaction technique. RESULTS: Melatonin pretreatment increased the expression of Cdkn1a and Rad50 in 8 and 24 h postradiations (2 and 8 Gy) (P < 0.05), and there was no significant difference in 48 h postradiation compared to the radiation-only and vehicle plus radiation (2 and 8 Gy) groups. CONCLUSIONS: Based on our results, pretreatment with melatonin (100 mg/kg) may ameliorates injurious effects of 2 and 8 Gy ionization radiation by increasing the expression level of Cdkn1a and Rad50 in rat peripheral blood and assist in DNA double-strand breaks repair, especially during the early postradiation.

The Treatment of Gliomas in Adulthood.

BACKGROUND: Gliomas are the most common intrinsic tumors of the brain, with an incidence of 6 per 100 000 persons per year. Recent years have seen marked changes in the diagnosis and treatment of gliomas, with molecular parameters now being an integral part of the diagnostic evaluation. METHODS: This review is based on pertinent articles retrieved by a selective search in PubMed, with special attention to the new WHO glioma classification. RESULTS: The classification of gliomas on the basis of additional molecular parameters enables more accurate prognostication and serves as a basis for therapeutic decision-making and treatment according to precisely specified algorithms. PET scanning with 18F-fluoroethyl tyrosine and 11C-methionine for the measurement of metabolic activity in gliomas has further refined the diagnostic evaluation. The median overall survival of patients with glioblastoma who have undergone resection of all tumor tissue with a disrupted blood-brain barrier (i.e., all contrast-enhancing tumor tissue) has been prolonged to up to 20 months. The 5-year survival of patients with WHO grade II gliomas is now as high as 97% after near-total resection. The surgical resection of all contrast-enhancing tumor tissue and subsequent radiotherapy and chemotherapy remain the key elements of treatment. New surgical strategies and new methods of planning radiotherapy have made these techniques safer and more effective. The percutaneous application of tumor-treating fields is a new therapeutic option that has gained a degree of acceptance. Accompanying measures such as psycho-oncology and palliative care are very important for patients and should be considered mandatory. CONCLUSION: The consistent application of the existing multimodal treatment options for glioma has led in recent years to improved survival. Areas of important current and future scientific activity include immunotherapy and targeted and combined chemotherapy, as well as altered neurocognition, modern approaches to palliative care, and complementary therapies.

Low serum level of miR-485-3p predicts poor survival in patients with glioblastoma.

MicroRNAs (miRNAs) are short noncoding RNAs that play critical roles in human malignancies and can be used as biomarkers for cancer. Until now, a number of biomarkers for prognosis of glioblastoma (GBM) have been reported in tumor tissues but only a few biomarkers in circulating fluid. Using a custom microarray, we previously identified 19 differentially expressed miRNAs in serum of patients with GBM. In this study, we investigated whether 3 of the 19 miRNAs in serum could be used as prognostic biomarkers for patients with GBM. We first validated the serum levels of 3 candidate miRNAs in an independent cohort of 24 GBM patients and 12 healthy volunteers by real-time quantitative reverse transcription PCR (qRT-PCR), and then evaluated the prognostic value of these miRNAs in a total of 36 GBM patients. The results show that the serum levels of the 3 miRNAs (miR-451a, miR-485-3p and miR-4298) determined by qRT-PCR are significantly different between 24 GBM patients and 12 healthy volunteers (all P <0.05) and are in concordance with the results of microarray analysis. High serum level of miR-451a is correlated with positive tumor O(6)-methylguanine-DNA methyltransferase (MGMT) expression (P = 0.040). Survival analysis showed that low serum miR-485-3p level is associated with poor progression-free survival (PFS) (P < 0.004) and overall survival (OS) (P < 0.023). Furthermore, univariate and multivariate Cox analyses demonstrated that that serum miR-485-3p expression is a significant independent prognostic factor for PFS and OS in GBM patients. In conclusion, serum miR-485-3p level is reduced and might be a potential prognostic biomarker in GBM patients.

Sequential Tracking of PD-L1 Expression and RAD50 Induction in Circulating Tumor and Stromal Cells of Lung Cancer Patients Undergoing Radiotherapy.

Purpose: Evidence suggests that PD-L1 can be induced with radiotherapy and may be an immune escape mechanism in cancer. Monitoring this response is limited, as repetitive biopsies during therapy are impractical, dangerous, and miss tumor stromal cells. Monitoring PD-L1 expression in both circulating tumor cells (CTCs) and circulating stromal cells (CStCs) in blood-based biopsies might be a practical alternative for sequential, noninvasive assessment of changes in tumor and stromal cells.Experimental Design: Peripheral blood was collected before and after radiotherapy from 41 patients with lung cancer, as were primary biopsies. We evaluated the expression of PD-L1 and formation of RAD50 foci in CTCs and a CStC subtype, cancer-associated macrophage-like cells (CAMLs), in response to DNA damage caused by radiotherapy at the tumor site.Results: Only 24% of primary biopsies had sufficient tissue for PD-L1 testing, tested with IHC clones 22c3 and 28-8. A CTC or CAML was detectable in 93% and 100% of samples, prior to and after radiotherapy, respectively. RAD50 foci significantly increased in CTCs (>7×, P < 0.001) and CAMLs (>10×, P = 0.001) after radiotherapy, confirming their origin from the radiated site. PD-L1 expression increased overall, 1.6× in CTCs (P = 0.021) and 1.8× in CAMLs (P = 0.004): however, individual patient PD-L1 expression varied, consistently low/negative (51%), consistently high (17%), or induced (31%).Conclusions: These data suggest that RAD50 foci formation in CTCs and CAMLs may be used to track cells subjected to radiation occurring at primary tumors, and following PD-L1 expression in circulating cells may be used as a surrogate for tracking adaptive changes in immunotherapeutic targets. Clin Cancer Res; 23(19); 5948-58. ©2017 AACR.

Mutations in XLF/NHEJ1/Cernunnos gene results in downregulation of telomerase genes expression and telomere shortening.

NHEJ1-patients develop severe progressive lymphocytopenia and premature aging of hematopoietic stem cells (HSCs) at a young age. Here we show a patient with a homozygous-NHEJ1 mutation identified by whole exome-sequencing that developed severe pancytopenia and bone marrow aplasia correlating with the presence of short telomeres. The mutation resulted in a truncated protein. In an attempt to identify the mechanism behind the short telomere phenotype found in the NHEJ1-patient we downregulated NHEJ1 expression in 293T and CD34+cells. This downregulation resulted in reduced telomerase activity and decreased expression of several telomerase/shelterin genes. Interestingly, cell lines derived from two other NHEJ1-deficient patients with different mutations also showed increased p21 expression, inhibition in expression of several telomerase complex genes and shortened telomeres. Decrease in expression of telomerase/shelterin genes did not occur when we inhibited expression of other NHEJ genes mutated in SCID patients: DNA-PK, Artemis or LigaseIV. Because premature aging of HSCs is observed only in NHEJ1 patients, we propose that is the result of senescence induced by decreased expression of telomerase/shelterin genes that lead to an inhibition of telomerase activity. Previous reports failed to find this connection because of the use of patient´s cells immortalized by TERT expression or recombined telomeres by ALT pathway. In summary, defective regulation of telomere biology together with defective V(D)J recombination can negatively impact on the evolution of the disease in these patients. Identification of telomere shortening is important since it may open new therapeutic interventions for these patients by treatments aimed to recover the expression of telomerase genes.

Tumor MGMT promoter hypermethylation changes over time limit temozolomide efficacy in a phase II trial for metastatic colorectal cancer.

BACKGROUND: Objective response to dacarbazine, the intravenous form of temozolomide (TMZ), in metastatic colorectal cancer (mCRC) is confined to tumors harboring O(6)-methylguanine-DNA-methyltransferase (MGMT) promoter hypermethylation. We conducted a phase II study of TMZ enriched by MGMT hypermethylation in archival tumor (AT), exploring dynamic of this biomarker in baseline tumor (BT) biopsy and plasma (liquid biopsy). PATIENTS AND METHODS: We screened 150 mCRC patients for MGMT hypermethylation with methylation-specific PCR on AT from FFPE specimens. Eligible patients (n = 29) underwent BT biopsy and then received TMZ 200 mg/m(2) days 1-5 q28 until progression. A Fleming single-stage design was used to determine whether progression-free survival (PFS) rate at 12 weeks would be ≥35% [H0 ≤ 15%, type I error = 0.059 (one-sided), power = 0.849]. Exploratory analyses included comparison between MGMT hypermethylation in AT and BT, and MGMT methylation testing by MethylBEAMing in solid (AT, BT) and LB with regard to tumor response. RESULTS: The PFS rate at 12 weeks was 10.3% [90% confidence interval (CI) 2.9-24.6]. Objective response rate was 3.4% (90% CI 0.2-15.3), disease control rate 48.3% (90% CI 32.0-64.8), median OS 6.2 months (95% CI 3.8-7.6), and median PFS 2.6 months (95% CI 1.4-2.7). We observed the absence of MGMT hypermethylation in BT in 62.7% of tumors. CONCLUSION: Treatment of mCRC with TMZ driven by MGMT promoter hypermethylation in AT samples did not provide meaningful PFS rate at 12 weeks. This biomarker changed from AT to BT, indicating that testing BT biopsy or plasma is needed for refined target selection.

Oxidative DNA damage is involved in cigarette smoke-induced lung injury in rats.

OBJECTIVE: Reactive oxygen species (ROS) induced by exogenous toxicants are suggested to be involved in carcinogenesis by oxidative modification of DNA. 8-Hydroxyl-2-deoxyguanosine (8-OHdG) has been considered as a reliable biomarker for oxidative DNA damage both in vivo and in vitro studies. But the effect of smoking on oxidative damage has not yet been fully elucidated. METHODS: Wistar rats were exposed to cigarette smoke at concentrations of 20 and 60 % for 30 min, twice/day for 45 weeks. Then the histopathology of lung tissues, levels of ROS, 8-OHdG, and total antioxidant (T-AOC), expression of DNA repair enzymes, e.g. 8-oxyguaine DNA glycosylase (OGG1), and MutThomolog 1 (Oxidized Purine Nucleoside Triphosphatase, MTH1) were determined in urine, peripheral blood lymphocytes, and lung tissue. RESULTS: The results showed that long-term cigarette smoke exposure can cause obvious damages of lung tissue in rats. In addition, a significant and cigarette smoke concentration-dependent increase in ROS and 8-OHdG were observed compared with the non-exposed control rats. In contrast, the expression of OGG1 and MTH1, and T-AOC levels were obviously decreased after long-term exposure to cigarette smoke. CONCLUSION: These findings indicate that long-term exposure to cigarette smoker increases ROS levels, decreases total antioxidant capacity, and interferes DNA repair capacity that eventually induces oxidative DNA damage, which appears to play an important role in cigarette smoke-induced lung injury in rats, and determination of 8-OHdG levels might be a useful method for monitoring oxidative damage in cigarette smokers.

Promoter methylation of MGMT gene in serum of patients with esophageal squamous cell carcinoma in North East India.

BACKGROUND: Promoter hypermethylation is a common event in human cancer. O6-methylguanine-DNA methyltransferase (MGMT) is a gene involved in DNA repair, which is methylated in a variety of cancers. We aimed to explore the methylation status of MGMT gene among the North Eastern population where esophageal cancer incidence and exposure to carcinogens like nitrosamines is high. MATERIALS AND METHODS: A total of 100 newly diagnosed esophageal cancer cases along with equal number of age, sex and ethnicity matched controls were included in this study. Methylation specific PCR was used to determine the MGMT methylation status in serum samples. RESULTS: Aberrant promoter methylation of the MGMT gene was detected in 70% of esophageal cancer cases. Hypermethylation of MGMT gene was found to be influenced by environmental factors like betel quid and tobacco which contain potent carcinogens like nitrosamines. Tobacco chewing and tobacco smoking habit synergistically with MGMT methylation elevated the risk for esophageal cancer development [adjusted OR=5.02, 95% CI=1.35-18.74; p=0.010 for tobacco chewing and Adjusted OR=3.00, 95% CI=1.22-7.36; p=0.014 for tobacco smoking]. CONCLUSIONS: Results suggest that the DNA hypermethylation of MGMT is an important mechanism for MGMT gene silencing resulting in esophageal cancer development and is influenced by the environmental factors. Thus MGMT hypermethylation can be used as a biomarker for esophageal cancer in high incidence region of North East India.

MGMT promoter methylation in plasma of glioma patients receiving temozolomide.

Promoter methylation of the O6-methylguanine-DNA methyltransferase (MGMT) gene plays a role in cellular response to alkylating agents. In the present study aimed to: (i) evaluate the concordance between MGMT promoter methylation status in tumor tissue and plasma; (ii) monitor MGMT promoter methylation status in plasma taken before and during temozolomide treatment; (iii) explore the value of MGMT promoter methylation status in plasma as a prognostic/predictive biomarker in glioma patients. We enrolled 58 patients with histologically confirmed glioma at different grades of malignancy. All patients underwent surgical resection and temozolomide treatment. Paraffin-embedded tumor tissue was available for 48 patients. Blood samples were collected from all patients before temozolomide treatment (baseline) and at each MRI examination for a 12-month period. MGMT promoter methylation status was assessed in both sample types by real time PCR with a specific probe. The frequency of MGMT promoter methylation was 60.4 % in tumor tissue and 41.38 % in plasma. MGMT promoter methylation status was concordant in the two sample types (Kappa = 0.75, 95 % confidence interval (CI) 0.57-0.93; p value <0.001). Overall and progression-free survival were longer in patients with methylated MGMT promoter. Mortality was higher in patients with unmethylated MGMT promoter, whether in tumor tissue [hazard ratio (HR) 2.21; 95 % CI 0.99-4.95] or plasma (HR 2.19; 95 % CI 1.02-4.68). Progression-free survival was shorter in patients with unmethylated MGMT promoter, whether in tissue (HR 2.30; 95 % CI 1.19-4.45) or plasma (HR 1.77; 95 % CI 0.95-3.30). The cumulative incidence of unmethylated MGMT promoter in plasma at baseline was 58 %, and reached virtually 100 % at 12 months. In conclusion MGMT promoter methylation status in tumor tissue and plasma was highly concordant, and both were associated with longer survival, supporting the role of the detection of methylated MGMT promoter in predicting treatment response. However we suggest caution in using plasma as a surrogate of tumor tissue due to possible false-negative results.

DNA repair gene expression level in peripheral blood and tumour tissue from non-small cell lung cancer and head and neck squamous cell cancer patients.

BACKGROUND: The nucleotide excision repair pathway is crucial for cellular DNA integrity and the ERCC1 helicase is also potentially involved in resistance to platinum-based chemotherapy, and high levels of ERCC1 mRNA in tumours have been associated with cisplatin resistance in different human cancers. The aim of this work was to investigate the correlation between DNA repair gene expression levels in tumour tissue, normal tissue and peripheral blood samples from patients with two common human cancers, non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (HNSCC), to test if blood gene expression could be a proxy for tumour tissue gene expression to predict response to platinum-based chemotherapy. METHODS: Using RT-qPCR we determined ERCC1, ERCC2, ERCC4, XPA, XPC, XRCC1, XRCC3, APEX, OGG1, MGMT mRNA levels in fresh NSCLC, normal lung and HNSCC tissue, as well as blood, from NSCLC and HNSCC patients who were treated surgically. RESULTS: Target gene expression in NSCLC and HNSCC tissue was higher than in blood. A statistically significant correlation (p<0.05) was found between target gene mRNA expression in tumour tissue and blood, in particular ERCC1, MGMT, XPC, XRCC1 and XRCC3 in NSCLC and APEX, ERCC1, ERCC2, ERCC4, XRCC1 and XRCC3 in HNSCC. CONCLUSIONS: The existence of a significant correlation between blood and tumour tissue expression of some genes of clinical interest, such as ERCC1 in NSCLC and HNSCC, could allow the introduction in clinical practice of a simple test that would measure mRNA levels of DNA repair genes in peripheral blood samples instead of tissue samples to determine prognostic and predictive factors in NSCLC and HNSCC patients.

Tumour and serum MGMT promoter methylation and protein expression in glioblastoma patients.

INTRODUCTION: Methylation of the promoter of the MGMT gene and MGMT protein expression are recognized as predictive markers for response to alkylating chemotherapy in glioblastoma (GB). MATERIAL AND METHODS: We have assessed MGMT methylation with the methylation-specific polymerase chain reaction (MSP) in tumor samples from 70 GB patients and in serum samples from 37 of these patients. We have also assessed MGMT protein expression by immunohistochemical (IHC) analysis in tissue samples from 63 of these patients. RESULTS: We found concordance between MGMT methylation status in tissue and serum (Cohen's Kappa = 0.586; p<0.0001). MSP for detection of non-methylated MGMT promoter in serum showed a sensitivity of 95.4% and a specificity of 60%, while the IHC methylation test showed a low specificity (8.9%). Patients whose MGMT promoter was methylated in tissue attained longer progression-free and overall survival. In the multivariate analysis, serum MGMT promoter methylation emerged as an independent factor for longer progression-free and overall survival. CONCLUSION: Serum-based MGMT methylation analysis offers a promising alternative to tumor-based MGMT analysis in cases where tissue samples are unavailable.

[Correlation of O6-methylguanine-DNA methyltransferase to radiation sensitivity of nasopharyngeal carcinoma].

OBJECTIVE: To assess the correlation of O6-methylguanine-DNA methyltransferase (MGMT) to radiation sensitivity of nasopharyngeal carcinoma (NPC). METHODS: Eighty randomly selected NPC patients were divided into high (+/++, n=62) and low (-/+/+, n=18) MGMT groups according to the results of MGMT detection using immunohistochemistry. All the patients received irradiation with external beam radiotherapy, and the radiation sensitivity of NPC was analyzed after the irradiation. RESULTS: The rates of high and low radiation sensitivity were 83.3% and 16.7% in low MGMT group, respectively, showing significant differences from those of the high MGMT group (45.2% and 54.8%, respectively, chi(2)=4.393, P=0.036). CONCLUSION: The content of MGMT correlates to the radiation sensitivity of NPC and may serve as valuable indicators for predicting the radiation sensitivity of NPC.

Aberrant methylation of APC, MGMT, RASSF2A, and Wif-1 genes in plasma as a biomarker for early detection of colorectal cancer.

PURPOSE: To identify epigenetic molecular makers in plasma for the early detection of colorectal cancer. EXPERIMENTAL DESIGN: We retrospectively analyzed the methylation status of 10 genes in fresh-frozen tissues and corresponding plasma samples from 243 patients with stage I and II sporadic colorectal cancer, 276 healthy individuals, and plasma from 64 colorectal adenoma patients using methylation-specific PCR. The methylation score (Mscore) was used to find molecular markers with high sensitivity and specificity. RESULTS: Of the 243 colorectal cancer tissues, methylation was detected in 18% for p14, 34% for p16, 27% for APC, 34% for DAPK, 32% for HLTF, 21% for hMLH1, 39% for MGMT, 24% for RARbeta2, 58% for RASSF2A, and 74% for Wif-1. Receiver operator characteristic curve analysis in plasma from 243 patients with cancer and 276 healthy individuals showed that the M score of any single gene had a sensitivity of <40% after controlling for age, sex, and tumor location. The specificity of the M score was not different between multigene and single gene analyses, but the sensitivity of the M score was significantly increased by multigene analysis. For all patients, the M score in a model including APC, MGMT, RASSF2A, and Wif-1 genes had a sensitivity of 86.5% and a specificity of 92.1% when 1.6 was used as a cutoff. In this model, the M score had a positive predictive value of 90.6% and a negative predictive value of 88.8%. CONCLUSION: The present study suggests that tumor-specific methylation of APC, MGMT, RASSF2A, and Wif-1 genes might be a valuable biomarker in plasma for the early detection of colorectal cancer.

Lack of prognostic significance of serum DNA methylation of DAPK, MGMT, and GSTPI in patients with non-small cell lung cancer.

BACKGROUND AND OBJECTIVES: To further improve the screening, diagnosis and therapy of patients with non-small cell lung cancer (NSCLC) additional diagnostic tools are desperately warranted. Aim of this study was to investigate the potential of the DNA methylation of DAPK, MGMT, and GSTPI in serum of patients with NSCLC as a prognostic molecular marker in this disease. METHODS: Seventy-six patients with NSCLC were included in this study. The analysis of DNA methylation in serum of patients was performed on pre-operative samples. Following DNA isolation and bisulfite-treatment, DNA methylation was analyzed by quantitative-methylation-specific real-time PCR with beta-actin as the internal reference gene. RESULTS: DNA methylation was detectable with following frequencies: DAPK 68.4%, MGMT 7.9%, GSTPI 0%. There were no associations between DNA methylation status and histology, tumor stage, grading or gender detectable. With a mean follow-up of 19.7 months the median survival was 26.3 months. There were no associations between the status of DNA methylation in patient's serum and prognosis detectable. CONCLUSION: The analysis of DNA methylation in serum of patients with NSCLC by quantitative-methylation-specific real-time PCR is technically feasible. Although our results suggest quantification of DNA methylation in serum not of prognostic significance in this disease, further studies are warranted to determine the future potential of this molecular approach.

Reduced expression of human DNA repair genes in esophageal squamous-cell carcinoma in china.

Epidemiological studies indicated that the incidence of esophageal squamous-cell carcinoma (ESCC) is associated with exposure to a variety of environmental factors. To determine whether the baseline expression of genes involved in DNA damage and repair induced by these carcinogens is associated with higher risk for ESCC, a case-control study was undertaken and the relative expression levels of six DNA repair genes (MGMT, hOGG1, XRCC1, XPD, hMLH1, and hMSH2) were determined in peripheral blood mononuclear cells (PBMC). One hundred patients with newly diagnosed, untreated ESCC and 117 healthy controls matched for age, gender, and residence were recruited. Expression levels of six genes were measured by quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR). Compared with controls, the relative expression levels of hMLH1, hMSH2, XRCC1, XPD, and MGMT, were significantly altered in ESCC patients. Using the median of relative expression level in controls as the cutoff point, results also demonstrated an increased risk for ESCC associated with reduced expression of hMSH2, XRCC, XPD, and MGMT. The expression levels of four genes (hMSH2, XRCC1, XPD, MGMT) present in PBMC were significantly correlated with increased risk for ESCC, in which there was reduced expression of MGMT, suggesting an important etiology role for MGMT expression in the initiation of ESCC in Huaian of China.