Investigation of the potential of miRNA candidates as non-invasive biomarkers for the diagnosis and follow-up of colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is the third most common cancer worldwide, and despite advances in treatment, molecular biomarkers are needed for both early diagnosis and prognosis monitoring. It is known that microRNAs (miRNA), one of the epigenetic mechanisms, are effective in the initiation and development of cancer by regulating the activity of tumor suppressors and/or oncogenes. In this study, the potential of the molecules let-7, miRNA125b, and miRNA30a, which are known to play a role in cellular processes, as biomarkers for colorectal cancer and their molecular mechanisms were investigated in this model. The aim was to evaluate the diagnostic, prognostic, and predictive utility of the target miRNAs in colorectal cancer patients. MATERIAL AND METHODS: The expression changes of miRNAs let-7, miRNA125b, and miRNA30a were investigated by miRNAs isolation and cDNA synthesis from the serum samples of 60 patients diagnosed with CRC or from the serum samples of 20 healthy individuals. The calculation was performed using the quantitative real-time polymerase chain reaction method to determine the expression level. The results were compared with clinical parameters. RESULT: An 8-fold decrease in the expression of let-7 and miRNA125b and a 60-fold decrease in the expression of miRNA30a were found in the serum samples of patients diagnosed with colorectal cancer (CRC) compared to the healthy group. A decrease in let-7 was observed in 53.3%, miRNA125b in 58.3%, and miRNA30a in 55% of patients. A significant correlation was found between the reduced expression status and the stage, lymph nodes, local recurrence, and metastasis (p < 0.05). The ROC analysis showed that the miRNA30a level could be a diagnostic biomarker for CRC (p < 0.001). No significant impact of target miRNA expression changes on overall disease survival was observed. CONCLUSION: It is thought that the target miRNA30a can be used for early diagnosis and screening and that the target miRNA let-7, miRNA125b, and miRNA30a can be used as non-invasive biomarkers for disease follow-up, with larger patient studies being conducted on CRC patients.

DNA methylation of KIFC1 gene in determination of histological diagnosis, prognosis and metastasis of lung cancer.

BACKGROUND: One of the main features of cancer, especially lung cancer (LC), is abnormal cell division. Abnormal expression of kinesin family member C1 (KIFC1/HSET), which is involved in mitotic cell division and ensures equatorial alignment of chromosomes during division, is observed in both premalignant and malignant lesions. There are no studies in the literature addressing the role of KIFC1 in the diagnosis and follow-up of LC. In this study, we investigated the epigenetic role of KIFC1 in the diagnosis, stage, and prognosis of various histological subtypes diagnosed with LC. MATERIAL AND METHODS: The expression and methylation status of the KIFC1 gene were examined after DNA/RNA isolation in tumor, conjugate normal tissue, and blood samples from 39 patients diagnosed with LC and in blood samples from 39 healthy controls. Changes in KIFC1 gene expression were examined by the Quantitative Real Time-PCR (qRT-PCR) method after cDNA synthesis following RNA isolation. The Methylation-Specific PCR (MSP) method was used to determine the methylation status of the KIFC1 gene. In this study, the expression/methylation profiles of the KIFC1 gene and the clinical and pathological characteristics of the patients were analyzed by statistical methods. RESULT: Hypomethylation was detected in 95.8% of the 62.1% of patients' tissues with increased KIFC1 gene expression. The expression level of the KIFC1 gene was found to be increased 3.2-fold in the tumor tissues of the patients compared with the conjugated normal tissues and 2.4-fold in the serum of the patients compared with the healthy serum. Statistical comparison of patients' clinical parameters and methylation and expression results revealed statistical significance between KIFC1 expression and metastasis, tumor stage and tumor grade. CONCLUSION: In conclusion, the increase in the expression level of the KIFC1 gene is higher in patients diagnosed with LC than in the healthy population, and therefore, the increase in the expression level of the KIFC1 gene due to hypomethylation can be used as a screening biomarker in LC. It can also be considered that the methylation profile of the KIFC1 gene may be a potential biomarker for determining the subtype of squamous cell carcinoma in LC. The results of the study need to be analyzed and continued with a larger number of patients.

The let-7 microRNA binding site variant in KRAS as a predictive biomarker for head and neck cancer patients with lymph node metastasis.

BACKGROUND: The let-7 family of microRNAs regulate multiple oncogenes including the KRAS gene and has been shown to play a critical role in carcinogenesis. In this study, we aimed to investigate polymorphic alterations of the let-7 miRNA binding site (rs61764370) in the 3'UTR region of the KRAS gene as a predictive biomarker for head and neck cancer (HNC) and to evaluate its association with clinicopathological parameters. MATERIAL AND METHODS: The frequency of the KRAS-LCS6 variant in 216 Turkish HNC' patients and 85 healthy individuals were evaluated. After extracting DNA from whole blood, the variant allele was analyzed by polymerase chain reaction and restriction fragment length polymorphism method. Genotype and allele frequencies were evaluated using the De-Finetti case-control program. RESULTS: 85.6 % of the patients were wild type, 13 % heterozygous and 1.4 % homozygous variant. Although the KRAS-LCS6 variant was not associated with the risk of HNC (p > 0.05), G homozygous variant allele was found to be significantly associated with HNC patients having lymph node metastasis [T vs G: OR(%95 CI)= 2.370 (1.03-5.41), p = 0.03, χ2 = 4.38]. It was found statistical significance between genotype frequencies and smoker patients [TT vs TG: OR(%95 CI)= 0.357 (0.13-0.97), p = 0.03, χ2 = 4.32] by using De-Finetti analysis. Statistical significance was observed between KRAS-LCS6 genotype frequencies and gender, smoking, alcohol, early/late-stage, lymph node metastasis according to univariate analysis and Cox proportional hazards regression model (p < 0.05). CONCLUSION: This is the first study to reveal the relationship between KRAS-LCS6 variant and lymph node metastasis in HNC. The LCS6 variant of the KRAS gene may be a candidate predictor risk biomarker for lymph node metastasis in HNC.

Evaluation of genetic and epigenetic changes of Tumor Necrosis Factor-Alpha gene in larynx cancer.

BACKGROUND: Tumor Necrosis Factor-Alpha (TNF-α) is a proinflammatory cytokine that plays a role in inflammation, which is one of the hallmarks of cancer, and its polymorphic variants have been associated with disease risk in many cancers in the literature. The aim of this study was to investigate four different polymorphic variants, differential methylation and expression status of the TNF-α gene and to determine the associations between these variants and disease risk, and to evaluate the relationship between the results and clinical parameters. We purposed to investigate the genetic and epigenetic alterations of the TNF-α gene in larynx cancer (LC). MATERIAL AND METHODS: After isolation of DNA/RNA from whole blood, tumor and normal tissue, polymorphic variant alleles differrential expression and methylation levels were analyzed by RFLP, semiquantitative RT-PCR, and restriction enzyme digestion, respectively. TNF-α expression and methylation levels were calculated using BIO1D software. The frequencies of the variants c.-238 G>A (rs361525), c.-857 C>T (rs1799724), c.-863 C>A (rs1800630), and c.-1031 T > C (rs1799964) in the promoter region of TNF-α in LC Turkish patients and healthy individuals were examined using the De-Finetti case-control program. Haplotype frequencies and linkage disequilibrium were analyzed using the SNPStats program. RESULTS: The frequency of genotype c.-1031 T > C was significantly lower in patients than in healthy individuals [TT vs TC: OR (%95CI) = 7.00 (1.75-27.93), p = 0.003, χ2 = 8.76]. The heterozygous variant of - 857 was associated with recurrence [T vs G: OR (%95CI) = 0.15 (0.02-0.95), p = 0.02, χ2 = 4.86]. For c.-238 G>A, c.-857 C>T, and c.-863 C>A, there was no statistically significant difference between the patient and healthy group in terms of disease risk. A significant association was found between c.-1031 T > C and disease risk of LC. Decreased expression was detected in 46% (23/50) and increased expression in 54% (27/50) of tumor tissue samples compared to the matched normal tissues of patients. Methylation-related loss of expression was detected in 53.3% (16/30) of patients. CONCLUSION: Our study is the first investigating four different polymorphic regions of the TNF-α promoter region and the expression/methylation status of TNF-α in the same LC patient and healthy cohort. According to our results, the c.-1031 T > C variant was reported to be significantly associated with a reduced risk of LC. In addition, the TNF-α variant c. -857 C>T suggests that it may be a potential biomarker for predicting the recurrence of LC. An association between c. -857 C>T variant and methylation-based expression status was observed.