Analysis of p53 protein expression levels on ovarian cancer tissue microarray using automated quantitative analysis elucidates prognostic patient subsets

P53 and TLR4 expression are prognostic markers informing progression free survival of advanced stage high grade serous ovarian cancer

OBJECTIVE

New prognostic biomarkers, and bio-signatures, are urgently needed to facilitate a precision medicine-based approach to more effectively treat patients with high-grade serous ovarian cancer (HGSC). In this study, we analysed the expression patterns of a series of candidate protein biomarkers.

METHODS

The panel of markers which included MyD88, TLR4, MAD2, PR, OR, WT1, p53, p16, CD10 and Ki67 was assessed using immunohistochemistry in a tissue microarray (TMA) cohort of n = 80 patients, composed of stage 3-4 HGSCs. Each marker was analysed for their potential to predict both overall survival (OS) and progression-free survival (PFS).

RESULTS

TLR4 and p53 were found to be individually predictive of poorer PFS (Log Rank, p = 0.017, p = 0.030 respectively). Cox regression analysis also identified high p53 and TLR4 expression as prognostic factors for reduced PFS (p53; HR=1.785, CI=1.036-3.074, p = 0.037 and TLR4; HR=2.175, CI=1.112-4.253, p = 0.023). Multivariate forward conditional Cox regression analysis, examining all markers, identified a combined signature composed of p53 and TLR4 as prognostic for reduced PFS (p = 0.023).

CONCLUSION

Combined p53 and TLR4 marker assessment may help to aid treatment stratification for patients diagnosed with advanced-stage HGSC.

The nuclear factor erythroid 2-related factor 2/p53 axis in breast cancer

One of the most important factors involved in the response to oxidative stress (OS) is the nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates the expression of components such as antioxidative stress proteins and enzymes. Under normal conditions, Kelch-like ECH-associated protein 1 (Keap1) keeps Nrf2 in the cytoplasm, thus preventing its translocation to the nucleus and inhibiting its role. It has been established that Nrf2 has a dual function; on the one hand, it promotes angiogenesis and cancer cell metastasis while causing resistance to drugs and chemotherapy. On the other hand, Nrf2 increases expression and proliferation of glutathione to protect cells against OS. p53 is a tumour suppressor that activates the apoptosis pathway in aging and cancer cells in addition to stimulating the glutaminolysis and antioxidant pathways. Cancer cells use the antioxidant ability of p53 against OS. Therefore, in the present study, we discussed function of Nrf2 and p53 in breast cancer (BC) cells to elucidate their role in protection or destruction of cancer cells as well as their drug resistance or antioxidant properties.

A chemotherapy response classifier based on support vector machines for high-grade serous ovarian carcinoma

Long-term outcome of high-grade serous epithelial ovarian carcinoma (HGSOC) remains poor as a result of recurrence and the emergence of drug resistance. Almost all the patients were given the same platinum-based chemotherapy after debulking surgery even though some of them are naturally resistant to the first-line chemotherapy. No method could verify this part of patients right after the surgery currently. In this study, we used 156 paraffin-embedded high-grade HGSOC specimens for immunohistochemical analysis with 37 immunology markers, and association between the expression levels of these markers and the chemoresponse were evaluated. A support vector machine (SVM)-based HGSOC prognostic classifier was then established, and was validated by a 95-patient independent cohort. The classifier was strongly predictive of chemotherapy resistance, and divided patients into low- and high-risk groups with significant differences progression-free survival (PFS) and overall survival (OS). This classifier may provide a potential way to predict the chemotherapy resistance of HGSOC right after the surgery, and then allow clinicians to make optimal clinical decision for those potentially chemoresistant patients. The potential clinical application of this classifier will benefit those patients with primary drug resistance.

Beside P53 and PTEN: Identification of molecular alterations of the RAS/MAPK and PI3K/AKT signaling pathways in high-grade serous ovarian carcinomas to determine potential novel therapeutic targets

Despite great histological and molecular heterogeneity, the clinical management of high-grade ovarian carcinomas remains unspecialized. As a major subgroup, high-grade serous ovarian carcinomas (HGSOCs) require novel therapies. In addition to utilizing conventional histological prognostic markers and performing oncogenetic investigations, the molecular diagnostic method of next generation sequencing (NGS) was performed to identify ‘druggable’ targets that could provide access to innovative therapy. The present study was performed in 45 HGSOC patients (mean age, 59.1 years; range, 25–87 years) with histologically proven HGSOC. Breast cancer 1/2 (BRCA1/2) germline mutations were screened in 17 patients with a familial or personal history of cancer, which was justified by oncogenetic investigations. Tumor protein 53 (P53) and phosphatase and tensin homolog (PTEN) expression were assessed in formalin-fixed paraffin-embedded tissues using immunohistochemistry. Somatic mutations of Kirsten rat sarcoma viral oncogene homolog, neuroblastoma RAS viral oncogene homolog (NRAS), B-Raf proto-oncogene, serine/threonine kinase, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA) and MET proto-oncogene, receptor tyrosine kinase (MET) were screened using NGS on DNA extracts from frozen tumor specimens obtained at diagnosis. With a median follow-up of 38 months (range, 6–93 months), 20 patients are alive, 10 patients are disease-free and 14 patients progressed within 6 months following platinum-based therapy. P53 overexpression was detected in 67% of patients and PTEN loss was detected in 38% of the patients. The overexpression of mutant P53 was found to be associated with a longer progression-free and overall survival. In total, 2 NRAS (exon 3), 3 PIK3CA (exon 5 and 10) and 5 MET mutations (exons 14 and 18) were detected. In HGSOCs, in addition to P53 and PTEN alterations, somatic genetic abnormalities can be detected using NGS and provide molecular rationale for targeted therapies, potentially offering novel therapeutic opportunities to patients.

High frequency of putative ovarian cancer stem cells with CD44/CK19 coexpression is associated with decreased progression-free intervals in patients with recurrent epithelial ovarian cancer

OBJECTIVE

Epithelial ovarian cancer (EOC) cells with CD44 and CK19 coexpression may represent a subset of ovarian cancer stem cells (OCSCs). This study was conducted to evaluate the correlation of the frequency of putative OCSCs (CD44 + CK19 + OCSCs) with the clinicopathologic features and the prognostic value in patients with recurrent advanced stage EOC.

METHODS

A retrospective study was carried out on 33 patients with EOC and a uniformly treated tissue microarray was constructed. A multiplexed, immunofluorescence-based method of automated in situ quantitative measurement of protein analysis was used for evaluation of the frequency or density of CD44 + CK19 + OCSCs in EOC.

RESULTS

The mean follow-up time was 42.8 ± 27.1 months. High frequency of EOC cells with CD44+ or CD44+/CK19+ was associated with chemoresistance (P = .033 and P = .02, respectively). Using K-M analysis with log-rank test, a high frequency of putative OCSCs was associated with short disease-free interval (7.9 months vs 20.9 months, P = .019). In univariable analysis, the frequency of OCSCs, International Federation of Gynecology and Obstetrics stage and residual tumor volume were significant predictor variables and were entered into multivariable analysis (P = .019, .037, and .005, respectively). Although no independent significant predictor was found, the frequency of putative OCSCs was the most promising predictor variable compared with the other 2 variables (hazard ratio = 2.344, P = .052).

CONCLUSION

Our findings suggest that high frequency of OCSCs (CD44+ and CK19+) in epithelial ovarian tumors correlates with short progression-free intervals.

A cytohistological study of p53 overexpression in ovarian neoplasms

Background:

The present study was undertaken to evaluate the diagnostic accuracy of imprint cytology in ovarian neoplasms, investigate the biological significance of p53 expression in malignant ovarian tumors and correlate it with histological type, grade and stage of tumor.

Material and Methods:

A total of 50 cases including 25 prospective and 25 retrospective cases were studied. Imprint cytology was performed on 25 ovarian tumors and compared with histopathological diagnosis. p53 immunohistochemistry was performed on all 50 cases.

Results:

On immunohistochemistry, all the benign tumors were negative for p53 while 42% of primary ovarian malignant tumors were positive. p53 expression was found to have a diagnostic value in differentiating benign from malignant tumors. p53 overexpression did not show any significant correlation with prognostic factors as stage of disease, grade of differentiation and type of tumor.

Conclusion:

The present study confirms the importance of p53 tumor suppressor gene expression as documented by immunohistochemistry in the differentiation of malignant and benign ovarian tumors.

SERS-based nanobiosensing for ultrasensitive detection of the p53 tumor suppressor

BACKGROUND

One of the main challenges in biomedicine is improvement of detection sensitivity to achieve tumor marker recognition at a very low concentration when the disease is not significantly advanced. A pivotal role in cancer defense is played by the p53 tumor suppressor, therefore its detection with high sensitivity may contribute considerably to early diagnosis of cancer. In this work, we present a new analytical method based on surface-enhanced Raman spectroscopy which could significantly increase the sensitivity of traditional bioaffinity techniques. p53 molecules were anchored to gold nanoparticles by means of the bifunctional linker 4-aminothiophenol (4-ATP). The characteristic vibrational bands of the p53-4-ATP nanoparticle system were then used to identify the p53 molecules when they were captured by a recognition substrate comprising a monolayer of azurin in molecules possessing significant affinity for this tumor suppressor. The Raman signal enhancement achieved by 4-ATP-mediated crosslinking of p53 to 50 nm gold nanoparticles enabled detect of this protein at a concentration down to 5 × 10⁻¹³ M.

The role of p53 as a surrogate marker for chemotherapeutical responsiveness in ovarian cancer

INTRODUCTION

In advanced ovarian cancers (OCs), p53 mutations are frequently observed. The objective of this study was to explore the value of the p53 mutational status, using four different techniques, in advanced OC patients as a predictive marker for responsiveness to platinum-based chemotherapy.

METHODS

One hundred and four, mostly serous papillary OC specimens were analyzed, of which all received a platinum containing chemotherapy after optimal cyto-reductive surgery. To verify the p53 mutational status, immunohistochemical staining with monoclonal antibodies, functional yeast assay (FASAY), single-strand conformation polymorphism analysis (SSCP) and genomic sequencing was performed in parallel.

RESULTS

Out of ten OC patients [2 low malignant potential (LMP)/8 G1] only two had a mutant p53, whereas eight showed a wild-type p53. 40 out of 63 (G2/3) patients with G2/3 OC showed mutant p53 and 23 patients showed a wild-type pattern. p53 status was significantly different between these two groups (LMP/G1 vs. G2/3) (P = 0.015). A progressive disease after chemotherapy completion was noted in 35.6% of the patients (26 out of 73); in 69.2%, a mutated p53 and in 30.8%, a wild-type p53 was found. Nine (12.3%) patients showed a complete response at the end of the first-line chemotherapy. Out of these nine patients five had a mutated and four a wild-type p53. A partial response was observed in nine (12.3%) patients of whom four had a mutated p53. With respect to response to first-line chemotherapy (six cycles of platinum containing regimen), the p53 status was not predictive; no statistical significance regarding the p53 mutational status was observed when the two extreme groups PD versus PR/CR were compared (P > 0.05).

CONCLUSION

In this study, the p53 mutational status was not predictive for responsiveness to platinum-based chemotherapy; but p53 was significantly more frequently mutated in poorly differentiated OCs.

Label-free electrochemical detection of the p53 core domain protein on its antibody immobilized electrode

We report quantitative results on interactions between a tumor suppressor protein, p53, also known as a prognostic cancer marker, and its antibody. The p53 antibody molecules immobilized on an (R)-lipo-diaza-18-crown-6 self-assembled monolayer (SAM)-modified gold disk electrode were shown to effectively capture the p53 protein by Western blot, quartz crystal microbalance, and electrochemical impedance experiments. The p53 protein thus captured modulated the ability of the electrode for charge transfer to and from a redox probe in the solution in a p53 concentration range of approximately 0.1-30 microg/mL. The same interaction was also observed in the human embryonic kidney cell lysate, demonstrating that the SAM-modified electrode can serve as a selective platform for electrochemically monitoring the cellular p53 concentration.

Modest effect of p53, EGFR and HER-2/neu on prognosis in epithelial ovarian cancer: a meta-analysis

BACKGROUND

P53, EGFR and HER-2/neu are the most frequently studied molecular biological parameters in epithelial ovarian cancer, but their prognostic impact is still unequivocal. We performed a meta-analysis to more precisely estimate their prognostic significance.

METHODS

Published studies that investigated the association between p53, EGFR and HER-2/neu status and survival were identified. Meta-analysis was performed using a DerSimonian-Laird model. Publication bias was investigated using funnel plots and sources of heterogeneity were identified using meta-regression analysis.

RESULTS

A total of 62 studies were included for p53, 15 for EGFR and 20 for HER-2/neu. P53, EGFR and HER-2/neu status had a modest effect on overall survival (pooled HR 1.47, 95% CI 1.33-1.61 for p53; HR 1.65, 95% CI 1.25-2.19 for EGFR and HR 1.67, 95% CI 1.34-2.08 for HER-2/neu). Meta-regression analysis for p53 showed that FIGO stage distribution influenced study outcome. For EGFR and HER-2/neu, considerable publication bias was present.

CONCLUSIONS

Although p53, EGFR and HER-2/neu status modestly influences survival, these markers are, by themselves, unlikely to be useful as prognostic markers in clinical practice. Our study highlights the need for well-defined, prospective clinical trials and more complete reporting of results of prognostic factor studies.

Protein expression of matriptase and its cognate inhibitor HAI-1 in human prostate cancer: a tissue microarray and automated quantitative analysis

Recent studies have suggested that matriptase, a transmembrane serine protease and its cognate inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1) are important in the progression of many cancers. Limited quantitative data are available on these proteins in prostate cancer. To validate the roles of matriptase and HAI-1 in prostate cancer and its progression, a prostate cancer tissue microarray was constructed. The tissue microarray includes 41 localized prostate cancers (Pca_local), 18 aggressive prostate cancers, 18 metastatic prostate cancers, 24 benign prostate hyperplasias, 18 high-grade intraepithelial neoplasias (HGPIN), and 41 benign prostate tissues. The cellular expression levels of matriptase and HAI-1 were quantified using automated quantitative analysis. We found that matriptase expression levels were significantly higher in Pca_local (P<0.0001) and HGPIN (P<0.05) compared with benign prostate tissue. Matriptase levels were significantly decreased in metastatic cancer when compared with all other tissue types (P<0.05). Compared with benign prostate tissue, HAI-1 expression levels were significantly higher in all proliferative prostate diseases (benign prostate hyperplasia, HGPIN, localized and aggressive cancers, and metastases) (P<0.001); yet, no significant differences were found in HAI-1 expression levels among the diseased tissue types. These results suggest that an increase of matriptase may be useful as a marker for detection of Pca_local, whereas a decrease of matriptase expression may signal prostate cancer progression. HAI-1 seems to be a marker of prostate epithelial cell proliferation.