Coincidence of PTPN22 c.1858CC and FCRL3 -169CC genotypes as a biomarker of preserved residual ß-cell function in children with type 1 diabetes.

BACKGROUND: Genotype-phenotype studies in type 1 diabetes (T1DM) patients are needed for further development of therapy strategies. OBJECTIVE: Our aims were to investigate the distribution of selected PTPN22 and FCRL3 gene polymorphisms and their associations with clinical course of disease in children with newly diagnosed T1DM from the Pomeranian region of Poland. SUBJECTS/METHODS: The prospective, longitudinal study of 147 children with newly diagnosed T1DM-autoimmune subtype was conducted. The PTPN22 c.1858T>C (rs2476601) and FCRL3 -169C>T (rs7528684) polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) and DNA sequencing. The frequencies of genotypes were compared between the study and population-matched control group (327 random anonymous samples from the Pomeranian region). Selected patients underwent a 24-monthly follow up [periodic re-evaluation of fasting C-peptide concentration (FCP) and hemoglobin A1c (HbA1c ) level]. RESULTS: A significantly lower coincidence of the PTPN22 c.1858CC and FCRL3 -169CC genotypes was found in the study group compared with controls (P = 0.04). The PTPN22 c.1858CC and FCRL3 -169CC genotype combination, restricted to female patients only, was associated with well-preserved residual ß-cell function throughout the entire follow up (prolonged FCP level increase up to the sixth month of disease, with further very stable dynamics-FCP median level ≥0.67 ng/mL without significant decrease up to the 24th month). HbA1c levels in this subgroup also remained the lowest during the observation period. CONCLUSIONS/INTERPRETATION: Ascertained phenomenon could be explained by an interacting mechanism of the two polymorphisms through estrogen-regulated nuclear factor kappa B signaling in regulatory T (Treg ) lymphocytes. This hypothesis, if confirmed, may lead to further development of Treg administration-based therapies.

Mutational analysis in podocin-associated hereditary nephrotic syndrome in Polish patients: founder effect in the Kashubian population.

Hereditary nephrotic syndrome is caused by mutations in a number of different genes, the most common being NPHS2. The aim of the study was to identify the spectrum of NPHS2 mutations in Polish patients with the disease. A total of 141 children with steroid-resistant nephrotic syndrome (SRNS) were enrolled in the study. Mutational analysis included the entire coding sequence and intron boundaries of the NPHS2 gene. Restriction fragment length polymorphism (RFLP) and TaqMan genotyping assay were applied to detect selected NPHS2 sequence variants in 575 population-matched controls. Twenty patients (14 %) had homozygous or compound heterozygous NPHS2 mutations, the most frequent being c.1032delT found in 11 children and p.R138Q found in four patients. Carriers of the c.1032delT allele were exclusively found in the Pomeranian (Kashubian) region, suggesting a founder effect origin. The 14 % NPHS2 gene mutation detection rate is similar to that observed in other populations. The heterogeneity of mutations detected in the studied group confirms the requirement of genetic testing the entire NPHS2 coding sequence in Polish patients, with the exception of Kashubs, who should be initially screened for the c.1032delT deletion.

A quality control program for mutation detection in KIT and PDGFRA in gastrointestinal stromal tumours.

BACKGROUND: Although most gastrointestinal stromal tumours (GIST) carry oncogenic mutations in KIT exons 9, 11, 13 and 17, or in platelet-derived growth factor receptor alpha (PDGFRA) exons 12, 14 and 18, around 10% of GIST are free of these mutations. Genotyping and accurate detection of KIT/PDGFRA mutations in GIST are becoming increasingly useful for clinicians in the management of the disease. METHOD: To evaluate and improve laboratory practice in GIST mutation detection, we developed a mutational screening quality control program. Eleven laboratories were enrolled in this program and 50 DNA samples were analysed, each of them by four different laboratories, giving 200 mutational reports. RESULTS: In total, eight mutations were not detected by at least one laboratory. One false positive result was reported in one sample. Thus, the mean global rate of error with clinical implication based on 200 reports was 4.5%. Concerning specific polymorphisms detection, the rate varied from 0 to 100%, depending on the laboratory. The way mutations were reported was very heterogeneous, and some errors were detected. CONCLUSION: This study demonstrated that such a program was necessary for laboratories to improve the quality of the analysis, because an error rate of 4.5% may have clinical consequences for the patient.

High frequency of BRCA1/2 germline mutations in consecutive ovarian cancer patients in Poland.

BACKGROUND: We estimated the prevalence of BRCA1/2 germline mutations in consecutive ovarian cancers and correlated the mutation status with clinicopathological features. METHODS: 151 consecutive primary ovarian cancer patients were screened for BRCA1/2 germline mutations. RESULTS: We identified BRCA1/2 germline mutations in 21 (13.9%) patients. Seventeen (81%) of carriers have BRCA1 and four (19%) have BRCA2 mutation. BRCA1/2 carriers have a distinctly longer overall survival than sporadic cases (log-rank, p=0.014). CONCLUSIONS: The relatively high proportion of BRCA1/2 carriers among unselected ovarian cancer patients indicates the necessity of searching for recurrent BRCA mutations in each case of ovarian carcinoma. This routine screen should be widened to include denaturing high performance liquid chromatography (DHPLC) analysis of both exons 11 of BRCA1 and BRCA2 genes in women with positive family history.

HER2 Amplification Has no Prognostic Value in Sporadic and Hereditary Ovarian Tumours.

Whereas HER2 amplification is a well-known phenomenon in breast tumours, its frequency and clinical importance in ovarian cancer have not been established. The aim of the study was to compare the frequency of HER2 amplification in hereditary (BRCA-positive) and sporadic (BRCA-negative) ovarian tumours and to estimate the association of this gene alteration on clinical outcome in ovarian cancer patients. We analysed HER2 amplification in 53 ovarian tumours: 20 from mutation carriers (18 in BRCA1 and 2 in BRCA2 gene) and 33 from non-carriers. Fluorescence in situ hybridization for HER2 was performed on 'touch' slides from frozen tumour samples or formalin-fixed, paraffin-embedded tissue. Our results indicate that high amplification (HER2: centromere ratio>5) is an infrequent phenomenon in ovarian tumours (6/53 cases). It occurs in both hereditary (4/20) and sporadic (2/33) tumours and no difference in the frequency of HER2 amplification exists between these groups. There is no significant difference in the clinical outcome of patients with HER2 amplified and non-amplified tumours (p = 0.3). Our results suggest a different biological role of HER2 amplification in ovarian and breast cancer.