ΔF508 mutation screening of healthy individuals from two populations in Espírito Santo State, Brazil.

The ΔF508 mutation is the most common cause of cystic fibrosis and its prevalence varies worldwide. For instance, up to 20-fold variations in its frequency have been recorded across different areas of Brazil. This study aimed to compare the distribution of ΔF508 among healthy individuals of admixed Portuguese descent from Espírito Santo (ES), a state in Southeastern Brazil, to that in a subpopulation of Pomeranian descent, considered to be an isolated group in which the European gene pool has been preserved, living in Santa Maria do Jetibá (also in ES). We found this mutation to be present at a frequency of 0.81% among the Pomeranian group, and 0% in the general ES population. No genetic differentiation was noted between the two populations examined (FST = 0.004), and these frequencies were found to be similar to those estimated in other states of Southeastern Brazil. Although the population of Santa Maria de Jetibá has retained Pomeranian traits, such as language, fair skin, and eye color, to date, there is no evidence of inbreeding in this group (FIS = -0.004). Screening healthy individuals for the ΔF508 mutation can facilitate genetic counseling for cystic fibrosis, as well as inform evolutionary and population studies.

HPRTYale proposed as a pathogenic variant for Lesch-Nyhan syndrome: a case report.

Lesch-Nyhan syndrome (LNS) is an X-linked recessive disorder caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT), an enzyme encoded by the HPRT1 gene. The classic disease phenotype described by Lesch and Nyhan in 1964 includes hyperuricemia, mental retardation, severe motor deficiency, and recurring self-mutilation. Here, we report the case of a family with 4 affected males and several female obligate carriers. In 1989, Fujimori et al. reported on a patient diagnosed with LNS who had an HPRT variant thereafter codenamed HPRTYale. The same patient was studied by Wilson et al. in 1986, who found no detectable HPRT enzymatic activity, even though normal HPRT mRNA and protein levels were observed. Disease severity is closely related to residual enzymatic activity, which fits the phenotype presented for this previously reported case, as well as for the patients we report on herein. As it has been reported in only one patient, this mutation is still considered a variant of unknown significance. The HPRTYale mutation is a G>C transversion that leads to a different amino acid with different biochemical properties at position 71, potentially causing the major lack of function. To evaluate the impact of this variant, we used the PolyPhen-2 software, which classified it as possibly damaging. Furthermore, the frequency of this mutant allele is likely extremely rare, since it has only been reported on twice, and a population frequency is not yet available. In conclusion, we propose that the HPRTYale variant is pathogenic, and should be included on lab reports hereafter.

Keratins 17 and 19 expression as prognostic markers in oral squamous cell carcinoma.

Five-year survival rates for oral squamous cell carcinoma (OSCC) are 30% and the mortality rate is 50%. Immunohistochemistry panels are used to evaluate proliferation, vascularization, apoptosis, HPV infection, and keratin expression, which are important markers of malignant progression. Keratins are a family of intermediate filaments predominantly expressed in epithelial cells and have an essential role in mechanical support and cytoskeleton formation, which is essential for the structural integrity and stability of the cell. In this study, we analyzed the expressions of keratins 17 and 19 (K17 and K19) by immunohistochemistry in tumoral and non-tumoral tissues from patients with OSCC. The results show that expression of these keratins is higher in tumor tissues compared to non-tumor tissues. Positive K17 expression correlates with lymph node metastasis and multivariate analysis confirmed this relationship, revealing a 6-fold increase in lymph node metastasis when K17 is expressed. We observed a correlation between K17 expression with disease-free survival and disease-specific death in patients who received surgery and radiotherapy. Multivariate analysis revealed that low expression of K17 was an independent marker for early disease relapse and disease-specific death in patients treated with surgery and radiotherapy, with an approximately 4-fold increased risk when compared to high K17 expression. Our results suggest a potential role for K17 and K19 expression profiles as tumor prognostic markers in OSCC patients.

MTHFR C677T and A1298C polymorphisms as predictors of radiotherapy response in head and neck squamous cell carcinoma.

The C677T and A1298C polymorphisms in methylene-tetrahydrofolate reductase (MTHFR), which regulates the release of active folate in the body, may have reduced activity. Given that folate participates in important intracellular pathways, such as nucleotide synthesis and biomolecule methylation, it seems plausible that patients with head and neck squamous cell carcinoma (HNSCC) may respond differently to radiotherapy treatments, based on genetic polymor-phisms. Therefore, this study sought to understand the role of these polymorphisms in HNSCC patient radiotherapy response. Genotypes were detected by PCR-RFLP after extraction of DNA from peripheral blood lymphocytes. Survival curves were analyzed by the Kaplan- Meier model, and significant differences were analyzed by the Wil-coxon test. Response to radiotherapy in patients with laryngeal SCC was significantly associated with the MTHFR C677T polymorphism (P = 0.030). Indeed, the presence of at least one T allele decreases the mortality rate up to 3-fold. Therefore, we propose that MTHFR C677T may represent a putative biomarker for radiotherapy prognosis in la-ryngeal SCC patients.

Prognostic significance of head and neck squamous cell carcinoma repair gene polymorphism.

The aims of this study were to analyze the polymorphisms XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, XPC Lys939Gln, ERCC1 Asn118Asn, and RAD51 -98G>C and to verify their influence on radiotherapy response and prognosis of patients with head and neck squamous cell carcinoma (HNSCC). Peripheral blood DNA was extracted from 311 patients and analyzed by PCR-RFLP. Our results showed that in irradiated oral and oropharyngeal patients, the 939Gln allele increased 6-fold local disease relapse risk (OR = 6.04; CI = 1.47-24.88) and over 2-fold the earliness of relapse (HR = 2.63; CI = 1.04-6.70). As for the XRCC3 polymorphism, multivariate analysis showed that the 241Met allele increases over 33-fold local relapse risk (OR = 33.64; CI = 3.23-350.85), over 12-fold earliness of relapse (HR = 12.55; CI = 2.47-63.73) and over 3-fold earliness of death (HR = 3.04; CI = 1.08-8.61). For polymorphism RAD51 -98, multivariate analysis showed that allele C increases over 3-fold the risk of relapse (OR = 3.13; CI = 1.12-8.78) and over 2-fold the earliness of relapse (HR = 2.84; CI = 1.25-6.47). For polymorphism XRCC1 Arg399Gln, multivariate analysis showed that the 399Gln allele increased the risk of local disease relapse for irradiated oral and oropharyngeal patients (OR = 3.35; CI = 1.10-10.13) by over 3-fold. Based on these results, we suggest that these polymorphisms may be useful markers of prognosis in HNSCC.

FAS ligand expression in inflammatory infiltrate lymphoid cells as a prognostic marker in oral squamous cell carcinoma.

Currently, the most important prognostic factor in oral squamous cell carcinoma (OSCC) is the presence of regional lymph node metastases, which correlates with a 50% reduction in life expectancy. We have previously observed that expression of hypoxia genes in the tumor inflammatory infiltrate is statistically related to prognosis in OSCC. FAS and FASL expression levels in OSCC have previously been related to patient survival. The present study analyzed the relationship between FASL expression in the inflammatory infiltrate lymphoid cells and clinical variables, tumor histology, and prognosis of OSCC. Strong FASL expression was significantly associated with lymph node metastases (P = 0.035) and disease-specific death (P = 0.014), but multivariate analysis did not confirm FASL expression as an independent death risk factor (OR = 2.78, 95%CI = 0.81-9.55). Disease-free and disease-specific survival were significantly correlated with FASL expression (P = 0.016 and P = 0.005, respectively). Multivariate analysis revealed that strong FASL expression is an independent marker for earlier disease relapse and disease-specific death, with approximately 2.5-fold increased risk compared with weak expression (HR = 2.24, 95%CI = 1.08-4.65 and HR = 2.49, 95%CI = 1.04-5.99, respectively). Our results suggest a potential role for this expression profile as a tumor prognostic marker in OSCC patients.