Prevalence of tumor BRCA1 and BRCA2 dysfunction in unselected patients with ovarian cancer

Objective: The therapeutic benefits of poly(ADP-ribose) polymerase inhibitors highlight the need to evaluate BRCA1/2 defects in tubal/ovarian cancer (OC). We sought to determine the pattern and disease characteristics associated with tumor BRCA1/2 mutations and BRCA1 methylation in women with OC. Methods: We obtained 111 OC specimens from 2 university hospitals and assessed BRCA1/2 mutations and BRCA1 methylation in tumor DNA. The frequency and pattern of BRCA1/2 defects were examined. Associations between patient/disease characteristics and BRCA1/2 defects were ascertained (Fisher's exact test). Platinum-free interval (PFI), progression-free survival (PFS), and overall survival (OS) based on the underlying BRCA1/2 defect were determined (Kaplan-Meier analysis [log-rank test]). Results: We observed a BRCA1/2 dysfunction rate of 40% (28/70) in high-grade serous tubal/ovarian cancer (HGSC), including 14.3% BRCA1 methylation (n=10), 7.1% BRCA1 mutation (n=5), and 18.6% BRCA2 mutation (n=13). Defects in BRCA1/2 genes were associated with stage III/IV HGSC (BRCA1 methylation: P=0.005 [stage III/IV] and P=0.004 [HGSC]; BRCA1/2 mutation: P=0.03 [stage III/IV] and P Conclusion: We observed a high tumor BRCA1/2 dysfunction rate in HGSC with a unique predominance of BRCA2 over BRCA1 mutations. While BRCA1/2 mutations conferred survival benefits in OC, no such association was observed with BRCA1 methylation.</p

The effect of silencing MyD88 and TLR4 mRNA on the chemoresponsive properties of SKOV-3 cells.

<p>SKOV-3 cells were left untransfected (Unt), transfected with negative control siRNA (siNeg), MyD88 targeting siRNA (siMyD88) or TLR4 targeting siRNA (siTLR4). The transfected cells were incubated for 72 hrs before either harvesting for mRNA analysis (A), for protein analysis (B) or treatment with paclitaxel (C). (A) MyD88 and TLR4 mRNA expression levels were evaluated by TaqMan RT-PCR. MyD88 and TLR4 mRNA expression was normalised to that of an endogenous control, B2M, and calibrated to that of untreated cells to establish the relative percentage of mRNA expression (n = 3, mean +SD). (B) MyD88 and TLR4 mRNA expression levels were evaluated by western blot analysis. GAPDH was used as a loading control. (C) Transfected cells were either left untreated, treated with DMSO (vehicle control) or 3.5 nM of paclitaxel (IC25). 48 hrs post treatment, cell viability was assessed by means of the CCK-8 assay. % cell viability rate was calculated by comparing the absorbance values for the vehicle control to the corresponding paclitaxel treated samples. Results are expressed as mean +SD, n = 3; *p<0.05, **p<0.01 (un-paired Student's t-test).</p

MyD88 expression and survival (Kaplan-Meier curves: median survival time shown in months).

<p>MyD88 positive tumours (n = 12) had significantly reduced progression-free survival (A) and overall survival (B) (p = 0.018 and p = 0.008, respectively).</p

Heterogeneous expression of monoclonal anti-TLR4.

<p>A: variable staining observed in adjacent epithelium within a benign serous cystadenoma (20x). B: focal strong staining within a serous carcinoma (40x).</p

TLR4/MyD88 and progression-free survival (Kaplan-Meier curves; median survival shown in months).

<p>TLR4 (A) or MyD88 (B) negative cases had significantly better PFS (15 & 18 months longer; p<0.05).</p

Quantification of immunohistochemical staining of TLR4 and MyD88 (0 = no staining, 1 = weak staining, 2 = moderate staining, 3 = strong staining).

<p>Quantification of immunohistochemical staining of TLR4 and MyD88 (0 =  no staining, 1 =  weak staining, 2 =  moderate staining, 3 =  strong staining).</p

TLR4/MyD88 and overall survival (Kaplan-Meier curves; median survival shown in months).

<p>Survival was longer in MyD88 (B) negative cases (by 19 months; p<0.05). The difference in survival associated with TLR4 (A) is not significant (p>0.5).</p

MiR-21 & miR-146a expression in the test series.

<p>Scatter plots showing relative microRNA expression with standard deviation (fold changes calculated via the 2^−ΔΔCt method). 20 EOC cases (serous carcinomas) grouped as MyD88+ or MyD88- based on protein expression; data shown relative to each group. Average expression of miR-21 & miR-146a increased in MyD88 negative EOC (p<0.05).</p

Distribution of TLR4 & MyD88 protein expression in all patient samples.

<p>Abbreviations: SD, standard deviation; FIGO, Federation International of Gynecology & Obstetrics; NOSE, normal ovarian surface epithelium.</p>†<p>TLR4, MyD88 expression by immunohistochemistry (score >4 =  positive).</p

miR-21 (A) and miR-146a (B) expression in chemosensitive and chemoresistant cancer cells.

<p>Data are expressed as fold change in expression with respect to A2780 cancer cells (with standard deviation).</p