Genetic, Surgical and Oncological Approach to Breast Cancer, with BRCA1, BRCA2, CDH1, PALB2, PTEN and TP53 Variants

Objective

The aim of this study was to determine the frequency of germline variants in BRCA1, BRCA2, CDH1, PALB2, PTEN and TP53 in patients admitted to a medical genetics clinic with breast cancer and to assess these identified variants according to published genetic, surgical and oncological perspectives.

Materials and Methods

Medical history, and cancer diagnosis information for 195 independent probands with operated breast cancer were collected from requisition forms and medical records. The exonic regions and exon-intron junctions in BRCA1, BRCA2, CDH1, PALB2, PTEN and TP53 genes were sequenced. Analysis of fastq files was performed on the Qiagen Clinical Insight-Analyse Universal with panel-specific pipeline and vcf files were interpreted clinically using Qiagen Clinical Insight-Interpret.

Results

Gene variants (pathogenic, likely pathogenic and variants of unknown significance) were detected in 53 (27.2%). Detailed information about the patients (age of diagnosis, family history, gender), cancer stage, tumour characteristics (ER, PR, human epidermal growth factor receptor 2 status) and all information related to the detected variants (gene, location, nucleotide and amino acid change, exon number, impact, mutation classification, dbSNP number and HGMD variant class) were assessed. In total, 58 mutations were identified including 14 novel, previously unreported variants.

Conclusion

Molecular characterization and identification of mutations have important implications for predictive, preventive, and personalized medicine, including genetic counseling and development of specific treatment protocols. We emphasize variants of unknown significance (VUS) as the clinical significance of VUS changes over time and variant classification is important for clinical molecular genetic testing and clinical guidance. This study may provide new insights into risk assessment for variants in CDH1, PALB2, PTEN and TP53, in addition to BRCA1 and BRCA2, which may prove useful for clinical management of breast cancer patients. Further studies are needed to identify the common gene variants in the Turkish population and evaluate the pathogenity of VUS.

Treatment of three hereditary leiomyomatosis patients with cryotherapy

Hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome is an autosomal dominant disorder characterized by cutaneous leiomyomas (CLM), uterine leiomyomas, and the increased risk of renal cell carcinoma. Piloleiomyomas develop from the arrectorpili muscle and are usually painful. For 22% of the affected patients, the pain is reported to impair their life quality. Since there are few case reports about cryotherapy for cutaneous leiomyomas in the literature, we have decided to present three patients who had painful cutaneous leiomyomas treated with cryotherapy.

Research of genetic bases of hereditary non-syndromic hearing loss

AIM

Hearing loss is the most common sensory disorder that affects approximately one per 1000 live births. With this project, we aimed to identify gene variants that were common causes of hearing loss in Turkey to contribute to the planning of genetic screening programs for hearing loss, as well as to improve genetic counseling to affected families.

MATERIAL AND METHODS

Twenty-one families with at least two affected individuals and parental consanguinity who presented with non-syndromic severe-to-profound sensorineural hearing loss were included in this study. We first screened for mutations in GJB2 and mitochondrial DNA 12S RNA genes. Subsequently, we genotyped the TMIE c.250C>T and SNP markers flanking the SLC26A4, MYO7A, MYO15A, OTOF, CDH23, TMIE, TECTA, PCDH15, TMC1, TMPRSS3, TMHS genes in the remaining twelve families without mutations in GJB2.

RESULTS

Screening for mutations in GJB2 gene showed c.[35delG];[35delG] mutation in four families, c.[35delG];[507C>A] mutation in two families, c.[35delG];[-23+1G>A] mutation in one family, and c.457G>A heterozygous mutation in one family. Genotyping SNP markers showed the c.[250C>T];[250C>T] mutation in TMIE in one family. A homozygous region with SNP genotypes was detected with the OTOF gene in one family, the TMPRSS3 gene in another family, and also a homozygous region was detected with TMHS, OTOF, and TMPRSS3 genes in another family.

CONCLUSIONS

Further research will be required to determine the genetic bases of hearing loss in families with non-syndromic hearing loss.