The performance of BRCA1 immunohistochemistry for detecting germline, somatic, and epigenetic BRCA1 loss in high-grade serous ovarian cancer

BACKGROUND

BRCA1 expression can be lost by a variety of mechanisms including germline or somatic mutation and promotor hypermethylation. Given the potential importance of BRCA1 loss as a predictive and prognostic biomarker in high-grade serous ovarian cancer, we sought to evaluate the utility of BRCA1 immunohistochemistry (IHC) in screening for BRCA1 loss by germline, somatic, and epigenetic mechanisms.

PATIENTS AND METHODS

Patients with advanced high-grade serous ovarian cancer who had previously undergone germline BRCA1 testing were identified. Samples from each tumor were stained for BRCA1 and reviewed independently by two pathologists blinded to BRCA status. Tumors with abnormal BRCA1 IHC and wild-type germline testing underwent further evaluation for somatic BRCA1 mutations and promoter hypermethylation. McNemar's test was used to determine the association of BRCA1 IHC with germline BRCA1 mutations and BRCA1 loss through any mechanism. Kaplan-Meier methods were used to estimate overall survival (OS), and the log-rank test was used to assess differences between groups.

RESULTS

Inter-rater reliability between the two pathologists on BRCA IHC interpretation was very good (kappa coefficient 0.865, P = 0.16; McNemar's test). BRCA1 IHC was abnormal in 36% (48/135) of cases. When compared with germline BRCA1 status, BRCA1 IHC had a high negative predictive value (95.4%) but a low positive predictive value (PPV, 52.1%). When accounting for promoter hypermethylation and somatic mutations as alternative methods of BRCA1 loss, the PPV rose to 87.5%. Five-year OS rate was 49.6% [95% confidence interval (CI) 26.3% to 69.3%] for patients with germline BRCA1 mutations, 50.4% (95% CI 27.5% to 69.5%) for germline wild-type BRCA1 and abnormal IHC, and 52.1% (95% CI 38.4% to 64.2%) for germline wild-type BRCA1 and normal IHC (P = 0.92).

CONCLUSIONS

BRCA1 IHC interpretation was a highly reproducible and accurate modality for detecting germline, somatic, or epigenetic mechanisms of BRCA1 loss. These results support further development of BRCA1 IHC as a potential biomarker for BRCA1 loss in high-grade serous ovarian cancer.

Screening miRNAs related to different subtypes of breast cancer with miRNAs microarray

AIM

The aim of this study was to screen miRNAs related to different subtypes of breast cancer and their target genes to identify new markers of tumor subtype.

MATERIALS AND METHODS

The miRNA expression profiles of breast cancer GSE38867 including 7 ductal carcinoma in situ breast (DCIS) cancer samples, 7 invasive breast cancer samples, 7 metastatic breast cancer samples, and 7 normal breast samples) were downloaded from Gene Expression Omnibus (GEO) database. Limma package in R software was applied to identify specific differentially expressed miRNAs of different subtypes of breast cancer. MicroRNA.org database source was used to predict the target genes of the identified differentially expressed miRNAs. We integrated the target genes and their interacted genes (predicted by STRING) into DAVID to perform the GO function and KEGG pathway analyses.

RESULTS

Compared to the normal control, a total of 21, 47, and 107 differentially expressed miRNAs were screened in DCIS, invasive and metastatic breast cancer, respectively. Specific differentially expressed miRNAs of the three subtypes were identified, including hsa-miR-99a and hsa-miR-151-3p for DCIS breast cancer, hsa-miR-145 and hsa-miR-210 for invasive breast cancer, and has-miR-205 and has-miR-361-5p metastatic breast cancer. Furthermore, 220, 43, 446, 307, 587 and 328 interaction pairs of the specific miRNA targets were predicted. Multiple GO functions and KEGG pathways were enriched with the miRNA targets and their interacted genes.

CONCLUSIONS

We screened the most representative miRNAs of the three different subtypes of breast cancer, which may act as the putative markers in the diagnosis of different subtypes of breast cancer.

Screening for key genes associated with invasive ductal carcinoma of the breast via microarray data analysis

The aim of this study was to identify key genes related to invasive ductal carcinoma (IDC) of the breast by analyzing gene expression data with bioinformatic tools. Microarray data set GSE31138 was downloaded from Gene Expression Omnibus, including 3 breast cancer tissue samples and 3 normal controls. Differentially expressed genes (DEGs) between breast cancer and normal control were screened out (FDR < 0.05 and |logFC| > 2). Coexpression between genes was examined with String, and a network was then constructed. Relevant pathways and diseases were retrieved with KOBAS. A total of 56 DEGs were obtained in the IDC of the breast compared with normal controls. A gene coexpression network including 27 pairs of genes was constructed and all the genes in the network were upregulated. Further study indicated that most of the genes in the coexpression network were enriched in ECM-receptor interaction (COL4A2, FN1, and HMMR) and nucleotide excision repair (CETN2 and PCNA) pathways, and that the most significantly related disease was autoimmune lymphoproliferative syndromes. A number of DEGs were acquired through comparative analysis of gene expression data. These findings are beneficial in promoting the understanding of the molecular mechanisms in breast cancer. More importantly, some key genes were revealed via gene coexpression network analysis, which could be potential biomarkers for IDC of the breast.

Escalation to weekly dosing recaptures response in adalimumab-treated patients with moderately to severely active ulcerative colitis

BACKGROUND

Patients with moderately to severely active ulcerative colitis occasionally do not respond to or lose initial response to maintenance dosing of anti-TNF therapy.

AIM

To report the efficacy of escalation from every other week (EOW) to weekly adalimumab dosing in patients from the clinical trial ULTRA 2 (NCT00408629), by week 8 response (i.e. response after adalimumab induction therapy).

METHODS

Week 52 remission, response, and mucosal healing rates were assessed in ULTRA 2 adalimumab-randomised patients who escalated to weekly dosing. Patients were stratified by week 8 response per partial Mayo score. Kaplan-Meier and logistic regression analyses estimated time to weekly dosing and defined predictors of escalation to weekly dosing, respectively. Adverse events were reported for patients receiving open-label adalimumab.

RESULTS

The rate of escalation to weekly dosing was 16.3% (20/123) for week 8 responders and 38.4% (48/125) for week 8 nonresponders. Week 52 remission, response and mucosal healing rates with weekly dosing were 20%, 45%, and 45% for week 8 responders and 2.1%, 25% and 29.2% for nonresponders, respectively (NRI). The median time to weekly dosing was 288 days for week 8 nonresponders and not estimable for responders. Prior anti-TNF use was a significant predictor of escalation to weekly dosing. Treatment-emergent adverse event rates were similar for patients receiving open-label EOW or weekly adalimumab.

CONCLUSIONS

Escalation to weekly adalimumab dosing demonstrated clinical benefits for patients who lost response to therapy and may be beneficial for patients not initially responding to induction therapy. No new safety risks were identified with weekly dosing.

Effects of rifampicin on osteogenic differentiation and proliferation of human mesenchymal stem cells in the bone marrow

This study was designed to investigate the effect of different concentrations of rifampicin on osteogenic differentiation and proliferation of mesenchymal stem cells (MSCs) in human bone marrow. Rifampicin treatment at 0, 4, 8, 16, 32, 64, and 128 mg/mL was applied throughout the whole process, from stromal cells purified from human bone marrow to differentiated bone cells. The effect of rifampicin on MSC proliferation was determined using the MTT assay. The effect of rifampicin on the expressions of type I collagen (COL1A1), osteopontin/bone Gla protein (OPN/BGP), and alkaline phosphatase (ALP) in human osteoblast cells were determined by real-time polymerase chain reaction, and the expressions of COL1A1, OPN/BGP, and the runt-related transcription factor (RUNX2) were determined by Western blot. Results showed that the proliferation of MSCs was significantly inhibited when the rifampicin concentration exceeded 32 mg/mL. In addition, increased rifampicin concentrations inhibited the formation of calcium nodules, OPN/BGP, and COL1A1 in osteoblasts after 28 days of induction. The RNA expressions of OPN/BGP, COL1A1, and ALP were significantly downregulated compared to those of the control group in osteoblasts after induction. The protein expressions of RUNX2, COL1A1, and OPN/BGP were also significantly downregulated compared to those of the control group after induction. In conclusion, rifampicin at exorbitant concentration exerts adverse effects on the proliferation of MSCs in human bone marrow and the differentiation of osteoblasts.

Monoallelic ABCC8 mutations are a common cause of diazoxide-unresponsive diffuse form of congenital hyperinsulinism

ABCC8 encodes a subunit of the β-cell potassium channel (KATP ) whose loss of function is responsible for congenital hyperinsulinism (CHI). Patients with two recessive mutations of ABCC8 typically have severe diffuse forms of CHI unresponsive to diazoxide. Some dominant ABCC8 mutations are responsible for a subset of diffuse diazoxide-unresponsive forms of CHI. We report the analysis of 21 different ABCC8 mutations identified in 25 probands with diazoxide-unresponsive diffuse CHI and carrying a single mutation in ABCC8. Nine missense ABCC8 mutations were subjected to in vitro expression studies testing traffic efficiency and responses of mutant channels to activation by MgADP and diazoxide. Eight of the 9 missense mutations exhibited normal trafficking. Seven of the 8 mutants reaching the plasma membrane had dramatically reduced response to MgADP or to diazoxide (<10% of wild-type response). In our cohort, dominant KATP mutations account for 22% of the children with diffuse unresponsive-diazoxide CHI. Their clinical phenotype being indistinguishable from that of children with focal CHI and diffuse CHI forms due to two recessive KATP mutations, we show that functional testing is essential to make the most reliable diagnosis and offer appropriate genetic counseling.

CT45A1 acts as a new proto-oncogene to trigger tumorigenesis and cancer metastasis

Cancer/testis antigen (CTA)-45 family (CT45) belongs to a new family of genes in phylogenetics and is absent in normal tissues except for testis, but is aberrantly overexpressed in various cancer types. Whether CT45 and other CTAs act as proto-oncogenes has not been determined. Using breast cancer as a model, we found that CT45A1, a representative CT45 family member, alone had a weak tumorigenic effect. However, its neoplastic potency was greatly enhanced in the presence of growth factors. Overexpression of CT45A1 in breast cancer cells markedly upregulated various oncogenic and metastatic genes, constitutively activated ERK and CREB signaling pathways, promoted epithelial-mesenchymal transition, and increased cell stemness, tumorigenesis, invasion, and metastasis, whereas silencing CT45A1 significantly reduced cancer cell migration and invasion. We propose that CT45A1 functions as a novel proto-oncogene to trigger oncogenesis and metastasis. CT45A1 and other CT45 members are therefore excellent targets for anticancer drug discovery and targeted tumor therapy, and valuable genes in the study of a molecular phylogenetic tree.

A polymorphism in the DNA repair domain of APEX1 is associated with the radiation-induced pneumonitis risk among lung cancer patients after radiotherapy

OBJECTIVE

To examine the association of tag single nucleotide polymorphisms (tagSNPs) (rs1130409, rs1760944, rs2307486 and rs3136817) in APEX1 with the risk of severe radiation-induced pneumonitis (RP) after radiotherapy among Han Chinese patients with lung cancer.

METHODS

A total of 168 patients with lung cancer who were receiving radiotherapy were prospectively recruited. RP was evaluated according to the Radiation Therapy Oncology Group. A case-control study was performed. The case group included patients with RP grade of ≥3, while the control group comprised patients with RP grades <3. Four tagSNPs of APEX1 were genotyped in 126 patients with complete follow-up by multi-SNaPshot® (Genesky Biotechnologies Inc., Shanghai, China) genotyping assays. RESULTS were assessed by a logistic regression model for RP risk and Mantal-Cox log-rank test for the cumulative RP probability by the genotypes.

RESULTS

rs1130409 was associated with severe RP. GT genotype of rs1130409 was significantly higher in patients with RP than in those of the control group [68.8% vs 41.8%; p = 0.025; resulting odds ratio (OR), 5.98]. Patients with lung cancer bearing the G allele had a 5.83-fold higher risk of RP than those with the wild TT genotype [OR = 5.83; 95% confidence interval (CI), 1.27-26.90; p = 0.024], and this was further confirmed by the binary regression adjusted by some confounding factors, including Karnofsky performance scale, concurrent chemotherapy-radiotherapy and lung volume receiving >30 Gy (OR = 6.96; 95% CI, 1.36-35.77; p = 0.02). rs1130409 was also associated with the time to occurrence of severe RP (p = 0.04). Three-dimensional model APEX1 protein showed that rs1130409 is located in the random coil structure corresponding to the DNA repair function region.

ADVANCES IN KNOWLEDGE

rs1130409 of APEX1 can be a predictor of RP grades ≥3 among patients with lung cancer.