Myoinositol and Metformin in the Prevention of Gestational Diabetes in High-Risk Patients: A Narrative Review.

Our hypothesis is that myoinositol and metformin in pregnant women with high-risk factors for glucose intolerance would reduce insulin resistance and consequently lower the incidence of gestational diabetes mellitus (GDM), a metabolic disorder of pregnancy characterized by maternal hyperglycemia due to deficient response to physiological insulin resistance, which may have a negative impact on perinatal outcome and long-term sequelae. In recent years, this pathology has become increasingly important given the global obesity epidemic and the delay in becoming pregnant, especially in industrialized countries. For this reason, the attempt to prevent, rather than cure, gestational diabetes is particularly important. In addition to lifestyle changes (especially diet and doing more exercise), myoinositol and metformin are the most promising factors at the moment, although not all RCTs published so far agree on their real effectiveness. A review of the articles published so far allows us to assume, albeit with some distinctions, that they can play a positive role.

Exploring the Relationship between Ovarian Cancer and Genital Microbiota: A Systematic Review and Meta-Analysis.

Ovarian cancer (OC) remains a significant health challenge globally, with high mortality rates despite advancements in treatment. Emerging research suggests a potential link between OC development and genital dysbiosis, implicating alterations in the microbiome composition as a contributing factor. To investigate this correlation, a meta-analysis was conducted following PRISMA and MOOSE guidelines, involving eight studies encompassing 3504 patients. Studies investigating the role of upper and inferior genital tract dysbiosis were included, with particular reference to HPV infection and/or history of pelvic inflammatory disease. The analysis revealed no significant difference in genital dysbiosis prevalence between OC patients and healthy controls. Although previous literature suggests associations between dysbiosis and gynecologic cancers, such as cervical and endometrial cancers, the findings regarding OC are inconclusive. Methodological variations and environmental factors may contribute to these discrepancies, underscoring the need for standardized methodologies and larger-scale studies. Despite the limitations, understanding the microbiome's role in OC development holds promise for informing preventive and therapeutic strategies. A holistic approach to patient care, incorporating microbiome monitoring and personalized interventions, may offer insights into mitigating OC risk and improving treatment outcomes. Further research with robust methodologies is warranted to elucidate the complex interplay between dysbiosis and OC, potentially paving the way for novel preventive and therapeutic approaches.

Anti-Severe Acute Respiratory Syndrome Coronavirus 2 IgG Is Present in the Amniotic Fluid of both Infected and Vaccinated Women at Second Trimester of Pregnancy: A Cohort Study.

INTRODUCTION: Pregnant women are protected from the complications of COVID-19 infection, thanks to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. The benefit of this vaccination to prevent morbidity and mortality in the fetus has not yet been completely elucidated. Our aim was to test the presence of anti-SARS-CoV-2 antibodies in the amniotic fluid during the second trimester of pregnancy and then to compare them to the antibody levels in maternal serum to evaluate their correlation and to improve amniotic fluid immunological characteristics knowledge. METHODS: This cohort study took place at the Policlinico G. Martino of Messina from September 2021 to February 2022; 22 pregnant women had amniocentesis: we analyzed serum and amniotic fluid samples of women who contracted the SARS-CoV-2 infection or vaccinated against the same virus within 1 year, and women never infected or vaccinated against it. Amniotic fluids and peripheral blood were collected to evaluate IgG anti-SARS-CoV-2 nucleocapsid and spike S1 protein antibodies. RESULTS: Patients vaccinated had higher S1 receptor-binding domain antibody levels both in amniotic fluid (p < 0.006; mean 68.70; standard deviation [SD] 85.46) and maternal blood (p < 0.005; mean 1,989.86; SD 3,777.15) than unvaccinated women. Anti-nucleocapsid antibodies were present in women who developed COVID infection both in amniotic fluid and maternal blood but not in unvaccinated women. There was a high correlation between the concentrations of anti-spike antibody levels in serum and amniotic fluid of vaccinated women (p < 0.001; R = 1.0) and of anti-nucleocapsid antibody levels in serum and amniotic fluid of women who developed COVID infection (p < 0.001; R = 0.93). CONCLUSION: Recent studies have shown that SARS-CoV-2 vaccination during pregnancy is safe. Moreover, we can assume that there is an early transplacental antibody transfer after anti-SARS-CoV-2 immunization to protect the fetus, and there is also a high correlation between levels of anti-nucleocapsid antibodies in blood and amniotic fluid of pregnant women previously infected.

Maternal and Neonatal Outcomes in Intrahepatic Cholestasis of Pregnancy.

The aims of our study were to evaluate the maternal and fetal outcomes of intrahepatic cholestasis of pregnancy (ICP). In this observational, retrospective case-control study, we included all pregnant women who gave birth with a diagnosis of ICP between January 2010 and December 2020 at the Unit of Obstetrics and Gynecology, University Hospital of Messina. The data were compared with those from a control group of pregnant women who did not have ICP. One hundred twenty-nine and eighty-five patients were included, respectively, in the study and in the control group. There was a significant difference between the two groups in the incidence of hypothyroidism, thrombophilia, gestational diabetes, gestational hypertension, postpartum hemorrhage, and preterm delivery, which were more frequent in the ICP patients. No neonatal adverse events were recorded, although a significant difference in the meconium-stained amniotic fluid condition was noted. After a 24-month follow-up, 48/129 patients with ICP accepted to be reassessed by liver ultrasound, elastographic examination, and liver function blood tests. No patient showed signs of chronic liver disease. This study confirmed a higher probability of adverse short-term maternal outcomes in ICP pregnant patients, but a lower probability of adverse short-term fetal outcomes and the absence of a long-term maternal risk of chronic liver disease.

Photodynamic therapy for intergluteal warts in a child affected by Rett syndrome.

Genital warts (GWs) are the most common sexually transmitted infections worldwide, caused by the human papillomavirus (HPV). The increasing prevalence of GWs in children has renewed the interest in therapeutic management which still presents a unique challenge, being influenced by many variables including size, quantity, and location of warts, as well as the presence of comorbidities. Conventional photodynamic therapy (C-PDT) has already shown encouraging results in the treatment of viral warts in adult patients, but its use is still not standardized in the pediatric population. On this topic, we report our experience with C-PDT in a difficult-to-treat area like the perianal region in a 12-year-old girl affected by Rett syndrome, an X-linked dominant neurological disorder, with a 10-month history of florid genital condylomatosis. After the third session of C-PDT, complete clearance of the lesions was achieved. Our case is paradigmatic of the potentiality of PDT to treat difficult lesions in difficult patients. Despite being expensive and time-consuming, this procedure has been demonstrated to be safe and well-tolerated. Lastly, the therapy is also well accepted by parents, due to its minimal invasiveness and the few side effects, compared to the other therapeutic options.

Exploring Surgical Strategies for Uterine Fibroid Treatment: A Comprehensive Review of Literature on Open and Minimally Invasive Approaches.

Background and Objectives: Uterine myomas represent one of the most prevalent pathologies affecting the female population. These benign neoplasms originate from the smooth muscular cells of the uterus, and they can be either single or multiple. Often associated with debilitating symptoms such as pelvic heaviness, pain, constipation, and urinary dysfunctions, the surgical management of myomectomy exhibits considerable variability. This diversity in approaches is influenced by factors such as the number and size of myomas, the patient's age, and overall clinical conditions. This study aims to elucidate and compare the advantages and disadvantages of different surgical approaches, specifically endoscopic procedures versus open surgery, providing valuable insights for clinical decision making. Materials and Methods: A comprehensive bibliographic search spanning from 2013 to 2023 was systematically conducted across databases including Medline, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov. The search utilized keywords such as "myomectomy laparoscopic and open", "myomectomy open and minimally invasive", "myomectomy open and laparoscopic", and "myomectomy open vs. laparoscopic." The research methodology, along with predetermined inclusion and exclusion criteria, was established prior to the search, ensuring a systematic and rigorous approach. Subsequently, data analysis was carried out. Results: Following the study selection process, 25 articles met the eligibility criteria for inclusion in this analysis. The average numbers of myomas were 3.7 (ranging from 1 to 13.7) and 5.4 (ranging from 1 to 13.5) for the minimally invasive surgery and open surgery groups, respectively. In terms of myoma size, the total averages across studies were 7 cm (ranging from 4.8 to 14) for the minimally invasive group and 8 cm (ranging from 3.9 to 11.2) for the open surgery group. The average pregnancy and delivery rates were 29.7% (ranging from 1.8 to 100) for the minimally invasive group and 28.5% (ranging from 1.8 to 100) for the open surgery group. Regarding complications, the average rate was 14.2% (ranging from 0 to 50) for the endoscopic group and 22.3% (ranging from 0 to 60.3) for the laparotomic group. Conclusions: In conclusion, a critical factor influencing the choice of surgical approach is primarily the size and quantity of fibroids. The mini-laparotomic approach emerges as a viable alternative to endoscopy, demonstrating favorable surgical outcomes and aesthetic results. Interestingly, the type of surgical procedure appears to have no significant impact on the pregnancy rate.

Minimally invasive management of a giant paratubal cyst in an adolescent female: Case report and review of the literature in the pediatric population.

Introduction: Paraovarian or paratubal cysts both define cysts located between the ovary and the fallopian tube. They are usually benign and frequently occur in the third and fourth decade of life. Paratubal cysts are defined as giant when they exceed the threshold of 150 mm. Methods: We report the case of a 15-year-old girl who complained about diffuse abdominal pain since 2 years that was diagnosed with a 196 mm × 90 mm × 267 mm giant paratubal cyst. We furthermore reviewed all the data published on 13 articles, published between 2006 and 2021, concerning giant paraovarian cyst (POC) in pediatric patients. Results: The giant mass of our 15-year-old patient was removed through a fertility-sparing laparoscopic surgery. Histopathological diagnosis of cystadenofibroma was made up, with no cytologic report of neoplastic cells. The incidence of POC in the pediatric and adolescent population attests around 4%. However, only 12.96% of them are defined giant (larger than 15 cm). Indeed, to the best of our knowledge, only 13 cases of giant paratubal cysts have been reported in adolescents. To accomplish diagnosis and differential diagnosis, accurate history and physical examination are mandatory. In all cases reported in the literature, further instrumental analyses were performed, including ultrasound, CT, and/or MRI scan. International Ovarian Tumor Analysis (IOTA) rules have not yet been validated in the pediatric population. Because of the advantages of the laparoscopic procedures, it is often preferred in pediatric population, also to help preserve as much ovarian parenchyma and salpinx if thought possible. The incidence of malignant adnexal masses in the pediatric population is reported to range from 4% to 9%, accounting for 1% of all pediatric cancers. Conclusion: Giant paratubal cysts in adolescent females are extremely rare and usually benign. A fertility-sparing laparoscopic surgery should be the preferable option whenever possible. Considering the rarity of these conditions, further investigations are needed to exclude the possibility of a malignant evolution.

Screening of GDM during COVID pandemic in an Italian setting: comparison between IADPSG and WHO '99 criteria.

BACKGROUND: During pandemic period, a single fast glycemia value (≥ 92 mg/dl) performed within the recommended time window for the risk level defined by the Italian guidelines, was considered an acceptable surrogate for GDM diagnosis following Italian Diabetes Association recomendations. METHODS: All pregnant women who performed an OGTT following Italian Guidelines from march 2020 to september 2021 and then delivered at our University Hospital were prospectively enrolled in this study. Primary outcome of the study was the number of women diagnosed with GDM with only the FPG value (≥ 92 mg/dl), following Italian Diabetes Societies recommendations for COVID 19 pandemic period. At the same time, the data of women who became diabetic according to the 1999 WHO criteria was collected too. The secondary outcome was the comparison of risk factors of women undergoing OGTT according to IADPSG and WHO'99 criteria for the diagnosis of GDM and associated clinical outcomes. RESULTS: The number of women with a diagnosis of GDM following Italian guidelines in the 18-month period considered was 161. Only 109 (67.7%) had a fast glucose value ≥ 92 mg/dl. No differences between IADPSG and WHO'99 groups in relation to risk factors, with the exception for overweight and obesity, and clinical outcomes. CONCLUSION: Recommendations of Italian Diabetes Societis for COVID 19 pandemic failed to recognize one third of GDM diagnosis. Clinical Trial Registration ClinicalTrials.gov, www. CLINICALTRIALS: gov , NCT05026840, August 30, 2021, 'retrospectively registered'.

Medullary Thyroid Carcinoma Mutational Spectrum Update and Signaling-Type Inference by Transcriptional Profiles: Literature Meta-Analysis and Study of Tumor Samples.

Medullary thyroid carcinoma (MTC) is a rare but aggressive tumor. Although RET and RAS genes are recognized drivers in MTC, associated downstream signaling pathways are largely unknown. In this study, we report 17 sporadic MTCs, collected at our institution, comprising patient-matched primary and lymph node metastatic tumors investigated for mutational and transcriptional profiles. As we identified two uncommon RET deletions (D898_E901del and E632_L633del), we also performed a literature review and meta-analysis to assess the occurrence of unconventional alterations in MTC, focusing on next-generation sequencing studies. We found that new gene alterations are emerging, along with the known RET/RAS drivers, involving not only RET by multiple concurrent mutations or deletions but also other previously underestimated cancer-related genes, especially in sporadic MTCs. In our MTC gene profiles, we found transcriptome similarity between patient-matched tissues and expression of immune genes only by a few samples. Furthermore, we defined a gene signature able to stratify samples into two distinct signaling types, termed MEN2B-like and MEN2A-like. We provide an updated overview of the MTC mutational spectrum and describe how transcriptional profiles can be used to define distinct MTC signaling subtypes that appear to be shared by various gene drivers, including the unconventional ones.

Ultrasound, macroscopic and histological features of serous epithelial ovarian carcinomas.

We present a video showing two cases of serous epithelial ovarian carcinomas. The first video shows clinical, ultrasound, macroscopic, and histological features of a patient with high grade serous ovarian carcinoma. The second video presents clinical, ultrasound, macroscopic, and histological features of a patient with low grade serous ovarian carcinoma.

Fusion imaging of ultrasound and MRI in the assessment of locally advanced cervical cancer: a prospective study.

BACKGROUND: Fusion imaging is a new diagnostic method that integrates MRI and ultrasound. It may improve the detection and staging of locally advanced cervical cancer. OBJECTIVE: To evaluate the feasibility and accuracy of fusion imaging in patients with locally advanced cervical cancer. METHODS: Patients with suspicion of locally advanced cervical cancer at clinical examination and/or imaging, who were candidates for neoadjuvant treatment (chemotherapy or chemoradiation) followed by surgery, were prospectively enrolled between March and November 2018. MRI, ultrasound, and fusion images were obtained before and after neoadjuvant treatment. Feasibility, success of the fusion examination, and time needed to perform fusion studies were evaluated. The rates of concordance between MRI and ultrasound before and after performing fusion, using Cohen, Spearman, and McNemar tests were calculated. The agreement between MRI and ultrasound examination, and the agreement between radiologist and gynecologist during the fusion technique in assessing local extension of disease and the presence of residual disease after neoadjuvant therapy, were also analyzed. The rates of concordance between MRI and ultrasound examination before and after performing fusion imaging, using Cohen's kappa and Spearman's rank correlation coefficient were calculated. A McNemar test was used to assess if there were statistical significant differences in the parameters' agreement before and after performing fusion imaging. RESULTS: 40 patients were selected and of these, 33 were analyzed. A total of 52 fusion examinations were performed: 33 (63.5%) of 52 at the time of diagnosis and 19 (36.5%) of 52 after neoadjuvant treatment. Fusion imaging was feasible in 50 (96%) of 52 studies. The median overall time of fusion execution was 13 min (range 6-30) and the time spent in performing a fusion examination decreased from the first to the last examination (20 vs 6 min). The agreement between MRI and ultrasound parameters increased after performing fusion, particularly for parametrial infiltration (74% vs 86%, p=0.014 for the right posterior parametrium; 66% vs 80%, p=0.008 for the left posterior parametrium, 70% vs 82%, p=0.014 for the right lateral parametrium). CONCLUSIONS: Fusion of MRI and ultrasound is feasible in patients with locally advanced cervical cancer and may increase the diagnostic accuracy of the single imaging methods. Fusion provides multiple diagnostic opportunities in gynecological oncology.

Cancer Associated Fibroblasts and Senescent Thyroid Cells in the Invasive Front of Thyroid Carcinoma.

Thyroid carcinoma (TC) comprises several histotypes with different aggressiveness, from well (papillary carcinoma, PTC) to less differentiated forms (poorly differentiated and anaplastic thyroid carcinoma, PDTC and ATC, respectively). Previous reports have suggested a functional role for cancer-associated fibroblasts (CAFs) or senescent TC cells in the progression of PTC. In this study, we investigated the presence of CAFs and senescent cells in proprietary human TCs including PTC, PDTC, and ATC. Screening for the driving lesions BRAFV600E and N/H/KRAS mutations, and gene fusions was also performed to correlate results with tumor genotype. In samples with unidentified drivers, transcriptomic profiles were used to establish a BRAF- or RAS-like molecular subtype based on a gene signature derived from The Cancer Genome Atlas. By using immunohistochemistry, we found co-occurrence of stromal CAFs and senescent TC cells at the tumor invasive front, where deposition of collagen (COL1A1) and expression of lysyl oxidase (LOX) enzyme were also detected, in association with features of local invasion. Concurrent high expression of CAFs and of the senescent TC cells markers, COL1A1 and LOX was confirmed in different TC histotypes in proprietary and public gene sets derived from Gene Expression Omnibus (GEO) repository, and especially in BRAF mutated or BRAF-like tumors. In this study, we show that CAFs and senescent TC cells co-occur in various histotypes of BRAF-driven thyroid tumors and localize at the tumor invasive front.

Senescent thyrocytes and thyroid tumor cells induce M2-like macrophage polarization of human monocytes via a PGE2-dependent mechanism.

BACKGROUND: Thyroid carcinoma includes several variants characterized by different biological and clinical features: from indolent microcarcinoma to undifferentiated and aggressive anaplastic carcinoma. Inflammation plays a critical role in thyroid tumors. Conditions predisposing to cancer, as well as oncogene activity, contribute to the construction of an inflammatory microenvironment that facilitates thyroid tumor progression. Moreover, oncogene-induced senescence, a mechanism tightly connected with inflammation, and able to restrain or promote cancer progression, is involved in thyroid cancer. The interactions between thyroid tumor cells and the microenvironment are not completely clarified. METHODS: We characterize in vitro the interplay between macrophages and senescent thyrocytes and tumor-derived cell lines, modeling early and late thyroid tumor stages, respectively. Purified peripheral blood-derived human monocytes were exposed to thyroid cell-derived conditioned medium (CM) and assessed for phenotype by flow cytometry. The factors secreted by thyroid cells and macrophages were identified by gene expression analysis and ELISA. The protumoral effect of macrophages was assessed by wound healing assay on K1 thyroid tumor cells. The expression of PTGS2 and M2 markers in thyroid tumors was investigated in publicly available datasets. RESULTS: Human monocytes exposed to CM from senescent thyrocytes and thyroid tumor cell lines undergo M2-like polarization, showing high CD206 and low MHC II markers, and upregulation of CCL17 secretion. The obtained M2-like macrophages displayed tumor-promoting activity. Among genes overexpressed in polarizing cells, we identified the prostaglandin-endoperoxide synthase enzyme (PTGS2/COX-2), which is involved in the production of prostaglandin E2 (PGE2). By using COX-2 inhibitors we demonstrated that the M2-like polarization ability of thyroid cells is related to the production of PGE2. Co-expression of PTGS2 and M2 markers is observed a significant fraction of human thyroid tumors. CONCLUSIONS: Our results demonstrate that both senescent thyrocytes and thyroid tumor cell lines trigger M2-like macrophage polarization that is related to PGE2 secretion. This suggests that the interaction with the microenvironment occurs at both early and late thyroid tumor stages, and favors tumor progression. The co-expression of PTGS2 gene and M2 markers in human thyroid carcinoma highlights the possibility to counteract tumor growth through COX-2 inhibition.

Altered Integrins Expression of Patients Affected by Cryptorchidism.

OBJECTIVES: The study aimed to investigate the expression of the integrin isoforms α7A and ß1A, expressed by myogenic precursor cells, and α7B and ß1D, expressed by mature muscle cells in the cremaster of patients affected by an undescended testis. METHODS: Fifteen samples of cremaster were obtained from patients undergoing surgery for an undescended testis. Thirty control specimens of cremaster were harvested from patients with congenital hydrocele or inguinal hernia. Immunofluorescent analysis was carried out using anti-α7A, ß1A, α7B, and ß1D integrin antibodies. Sections were observed using confocal laser scanning microscopy. RESULTS: As compared with controls, a significant loss of a α7B (p = 0.0355) and ß1D (p = 0.0069) integrins and a higher expression of α7A (p = 0.0003) and ß1A (p = 0.0150) was detected in the cremaster of patients affected by an undescended testis. CONCLUSIONS: Our data document a critical alteration of the cytoskeleton of cremasteric smooth muscle cells in patients with an undescended testis. This might explain the altered function in smooth muscle cells in cremaster implied during testicular descent. We therefore speculate that the postnatal splicing of α7A to α7B and of ß1A to ß1D integrins is delayed. This could account for the common clinical scenario of spontaneous descent of the testes in the first months of life.

Correction: miR-451a is underexpressed and targets AKT/mTOR pathway in papillary thyroid carcinoma.

[This corrects the article DOI: 10.18632/oncotarget.7262.].

Circulating miR-375 as a novel prognostic marker for metastatic medullary thyroid cancer patients.

This study aimed to identify circulating miRNAs as novel non-invasive biomarkers for prognosis and vandetanib response in advanced medullary thyroid cancer (MTC) patients. We prospectively recruited two independent cohorts of locally advanced/metastatic MTC patients including a subgroup of vandetanib-treated subjects: a discovery cohort (n = 20), including matched plasma/tissue samples (n = 17/20), and a validation cohort, yielding only plasma samples (n = 17). Plasma samples from healthy subjects (n = 36) and MTC patients in remission (n = 9) were used as controls. MTC (n = 17 from 8 patients included in discovery cohort) and non-neoplastic thyroid specimens (n = 3) were assessed by microarray profiling to identify candidate circulating miRNAs. qRT-PCR and in situ hybridization were carried out to validate the expression and localization of a selected miRNA within tissues, and qRT-PCR was also performed to measure miRNA levels in plasma samples. By microarray analysis, we identified 51 miRNAs differentially expressed in MTC. The most overexpressed miR, miR-375, was highly expressed by C cells compared to other thyroid cells, and more expressed in MTC than in reactive C-cell hyperplasia. MTC patients had significantly higher miR-375 plasma levels than healthy controls (P < 0.0001) and subjects in remission (P = 0.0004) as demonstrated by qRT-PCR analysis. miR-375 plasma levels were not predictive of vandetanib response, but, notably, high levels were associated with significantly reduced overall survival (HR 10.61, P < 0.0001) and were a strong prognostic factor of poor prognosis (HR 6.24, P = 0.00025) in MTC patients. Overall, our results unveil plasma miR-375 as a promising prognostic marker for advanced MTC patients, to be validated in larger cohorts.

miR-451a is underexpressed and targets AKT/mTOR pathway in papillary thyroid carcinoma.

Papillary Thyroid Carcinoma (PTC) is the most frequent thyroid cancer. Although several PTC-specific miRNA profiles have been reported, only few upregulated miRNAs are broadly recognized, while less consistent data are available about downregulated miRNAs. In this study we investigated miRNA deregulation in PTC by miRNA microarray, analysis of a public dataset from The Cancer Genome Atlas (TCGA), literature review and meta-analysis based on a univocal miRNA identifier derived from miRBase v21. A list of 18 miRNAs differentially expressed between PTC and normal thyroid was identified and validated in the TCGA dataset. Furthermore, we compared our signature with miRNA profiles derived from 15 studies selected from literature. Then, to select possibly functionally relevant miRNA, we integrated our miRNA signature with those from two in vitro cell models based on the PTC-driving oncogene RET/PTC1. Through this strategy, we identified commonly deregulated miRNAs, including miR-451a, which emerged also by our meta-analysis as the most frequently reported downregulated miRNA. We showed that lower expression of miR-451a correlates with aggressive clinical-pathological features of PTC as tall cell variant, advanced stage and extrathyroid extension. In addition, we demonstrated that ectopic expression of miR-451a impairs proliferation and migration of two PTC-derived cell lines, reduces the protein levels of its recognized targets MIF, c-MYC and AKT1 and attenuates AKT/mTOR pathway activation.Overall, our study provide both an updated overview of miRNA deregulation in PTC and the first functional evidence that miR-451a exerts tumor suppressor functions in this neoplasia.

The modifier role of RET-G691S polymorphism in hereditary medullary thyroid carcinoma: functional characterization and expression/penetrance studies.

BACKGROUND: Hereditary medullary thyroid carcinoma (MTC) is caused by germ-line gain of function mutations in the RET proto-oncogene, and a phenotypic variability among carriers of the same mutation has been reported. We recently observed this phenomenon in a large familial MTC (FMTC) family carrying the RET-S891A mutation. Among genetic modifiers affecting RET-driven MTC, a role has been hypothesized for RET-G691S non-synonymous polymorphism, though the issue remains controversial. Aim of this study was to define the in vitro contribution of RET-G691S to the oncogenic potential of the RET-S891A, previously shown to harbour low transforming activity. METHODS: The RET-S891A and RET-G691S/S891A mutants were generated by site-directed mutagenesis, transiently transfected in HEK293T cells and stably expressed in NIH3T3 cells. Their oncogenic potential was defined by assessing the migration ability by wound healing assay and the anchorage-independent growth by soft agar assay in NIH3T3 cells stably expressing either the single or the double mutants. Two RET-S891A families were characterised for the presence of RET-G691S. RESULTS: The functional studies demonstrated that RET-G691S/S891A double mutant displays a higher oncogenic potential than RET-S891A single mutant, assessed by focus formation and migration ability. Moreover, among the 25 RET-S891A carriers, a trend towards an earlier age of diagnosis was found in the MTC patients harboring RET-S891A in association with RET-G691S. CONCLUSIONS: We demonstrate that the RET-G691S non-synonymous polymorphism enhances in vitro the oncogenic activity of RET-S891A. Moreover, an effect on the phenotype was observed in the RET-G691S/S891A patients, thus suggesting that the analysis of this polymorphism could contribute to the decision on the more appropriate clinical and follow-up management.