Epidemiological and molecular evaluation of BRAF, KRAS, NRAS genes and MSI in the development of colorectal cancer.

BACKGROUND AND OBJECTIVES: KRAS, NRAS, BRAF mutations and microsatellite instability (MSI) can be associated with Colorectal Cancer (CRC) development. MATERIAL AND METHODS: We evaluated 828 medical records of CRC patients from a school hospital from January/2016 to December/2020. Variables such as age, gender, ethnicity, literacy level, smoking, alcoholism, primary anatomical site, tumor staging, presence of BRAFV600E, KRAS, NRAS mutations and MSI , survival and metastasis were identified. The statistical analyses were performed (p < 0.05 was considered significant). RESULTS: There was a predominance of males (51.93%), whites (90.70%), low education (72.34%), smokers (73.79%), and non-alcoholics (79.10%). Rectum was the most affected site (42.14%), advanced tumor stage was most prevalent (62.07%), and metastasis occurred in (64.61%). Of the enrolled patients; 204 were investigated for BRAF mutation and detected in (2.94%); 216 for KRAS gene and detected in (26.08%); 210 for NRAS gene, and detected in (25.36%); 370 for MSI and detected in (44.68%). A significant association of CRC with NRAS mutation and alcohol habit (p = 0.043) was observed. The presence of MSI was associated with primary site proximal colon (p < 0.000), distal colon (p = 0.001) and rectum (p = 0.010). CONCLUSION: Patients with CRC are male, over 64 years old, white, with low education, smokers and non-alcoholics. The most affected primary site is rectum in advanced stage with metastasis. CRC is associated with NRAS mutation and alcohol habit, there is increased risk for primary site of proximal colon and MSI; decreased risk for distal colon and rectum in the presence of MSI.

Gene Polymorphisms Involved in Folate Metabolism and DNA Methylation with the Risk of Head and Neck Cancer.

BACKGROUND: Folate is essential for DNA synthesis, repair, and methylation. Polymorphisms in genes associated with folate metabolism may alter these processes and, consequently, modulate cancer development. AIM: We aimed to assess DNMT3B -149C/T (rs2424913), DNMT3B -283T/C (rs6087990), DNMT3B -579G/T (rs2424909), DHFR 19-pb ins/del (rs70991108), SHMT1 1420C/T (rs1979277), and TYMS 28-bp tandem repeat (rs34743033) polymorphisms with risk of head and neck cancer. METHODS: A case-control study was conducted in 1,086 Brazilian individuals. Real-time and conventional polymerase chain reactions-PCR were performed for genotyping the polymorphisms. RESULTS: The single nucleotide polymorphism (SNP), DNMT3B -283T/C, revealed a higher risk of head and neck squamous cell carcinoma (HNSCC) when compared with the C group in the codominant (p < 0.001), dominant (p <0.001), and overdominant (p= 0.001) models for T/C and C/C genotypes. DNMT3B -149C/T and DNMT3B -579G/T revealed no association between groups in any model. The DHFR 19-pb ins/del polymorphism protected against HNSCC development compared to the C group by the codominant (p < 0.001), dominant (p < 0.001), and overdominant (p < 0.001) models. In the TYMS, the 3R/3R genotype had a protective effect against HNSCC development compared with the C group by the recessive models (p= 0.009). In contrast, SHMT1 1420 C/T presented no association between the HNSCC and C groups. DHFR 19-pb ins/del polymorphisms protected against oral cavity cancer (p= 0.003), and only TYMS-28 3R/3R decreased the risk of tumor progression (p= 0.023). In the Kaplan-Meier curve, an association was found between DHFR ins/ins and TYMS -28 3R carriers with respect to relapse-free time; further, DNMT3B -579 T and TYMS-28 2R/2R carriers had longer survival times. CONCLUSION: DNMT3B -283T/C is associated with higher risk, whereas DHFR 19-pb ins/del and TYMS 28 3R/3R protect against head and neck cancer. We also highlighted the association of TYMS 3R/3R genotype carriers with relapse-free cancer protection and survival time.

Clinical, Epidemiological and Histopathological Aspects in Patients with Hepatocellular Carcinoma Undergoing Liver Transplantation

Background: Hepatocellular Carcinoma (HCC) is the primary liver cancer with high incidence and mortality rates. Currently one of the major etiologies for liver disease, HCC and liver transplantation is nonalcoholic fatty liver disease (NAFLD). The aim of the present study was to evaluate the epidemiological, histopathological and clinical aspects of HCC transplant patients, with emphasis on NAFLD etiology. Methods: This study included all HCC patients submitted to liver transplantation from 2010 to 2016 of the University Reference Center. The analyzed variables were age, gender, ethnicity, causes that led to liver transplantation, alpha-fetoprotein (AFP) dosage, histological aspects, recurrence, survival and NAFLD. Results: A total of 60 patients were included in the study being 80% men with a mean age of 58.3 ± 10.6 years. All patients were cirrhotic. The causes that led to the transplantation were the presence of the hepatitis C virus (HCV) (56.6% of the patients), an association of the virus with alcohol (20%), the presence of the hepatitis B virus (HBV) (20%), alcoholic liver disease (ALD) (50.9%) and NAFLD (25%). Of the latter, eight were diagnosed pre-transplantation and seven were NAFLD carriers without a previous diagnosis. Regarding the Edmondson-Steiner histological classification, 58.5% of the patients were classified as grade ≤ II. Conclusions: There is predominance of male patients with a mean age of 58.3 years. Degree ≤ II is the most frequent to the Edmondson-Steiner histological classification in the evaluated casuistic. HCV, ALD and NAFLD is the most common etiological agents found in the study. The (high) underestimated prevalence of NAFLD in the pre-transplanted patients is due to the fact that all patients presented cirrhosis, masking NAFLD signals.

Prevalence of the GJB2 mutations and the del(GJB6-D13S1830) mutation in Brazilian patients with deafness.

Mutations in the GJB2 gene are the most common cause of sensorineural non-syndromic deafness in different populations. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in many countries. The aim of this study was to determine the prevalence of GJB2 mutations and the del(GJB6-D13S1830) mutation in non-syndromic deaf Brazilians. The 33 unrelated probands were examined by clinical evaluation to exclude syndromic forms of deafness. Mutation analysis in the GJB2 gene and the testing for the del(GJB6-D13S1830) were performed in both the patients and their family members. The 35delG mutation was found in nine of the probands or in 14 of the mutated alleles. The V37I mutation and the del(GJB6-D13S1830) mutation were also found in two patients, both are compound heterozygote with 35delG mutation. These findings strengthen the importance of genetic diagnosis, providing early treatment, and genetic counseling of deaf patients.