Mutations in the KRAS gene in ovarian tumors

Role of RAS signaling in ovarian cancer

The RAS family of proteins is among the most frequently mutated genes in human malignancies. In ovarian cancer (OC), the most lethal gynecological malignancy, RAS, especially KRAS mutational status at codons 12, 13, and 61, ranges from 6-65% spanning different histo-types. Normally RAS regulates several signaling pathways involved in a myriad of cellular signaling cascades mediating numerous cellular processes like cell proliferation, differentiation, invasion, and death. Aberrant activation of RAS leads to uncontrolled induction of several downstream signaling pathways such as RAF-1/MAPK (mitogen-activated protein kinase), PI3K phosphoinositide-3 kinase (PI3K)/AKT, RalGEFs, Rac/Rho, BRAF (v-Raf murine sarcoma viral oncogene homolog B), MEK1 (mitogen-activated protein kinase kinase 1), ERK (extracellular signal-regulated kinase), PKB (protein kinase B) and PKC (protein kinase C) involved in cell proliferation as well as maintenance pathways thereby driving tumorigenesis and cancer cell propagation. KRAS mutation is also known to be a biomarker for poor outcome and chemoresistance in OC. As a malignancy with several histotypes showing varying histopathological characteristics, we focus on reviewing recent literature showcasing the involvement of oncogenic RAS in mediating carcinogenesis and chemoresistance in OC and its subtypes.

Mutation analysis and genomic imbalances of cells found in effusion fluids from patients with ovarian cancer

Ovarian carcinomas and carcinosarcomas often cause malignant effusions, an accumulation within serous cavities of fluid containing cancer cells. Few studies have focused on the molecular alterations and genetic mechanisms behind effusion formation. The present study investigated the mutation status of TP53, PIK3CA, KRAS, HRAS, NRAS and BRAF in effusion fluids from 103 patients with ovarian cancer. In addition, array Comparative Genomic Hybridization (aCGH) analysis was performed on 20 effusions from patients with high-grade serous carcinoma (10 cases positive for TP53 mutation and 10 with TP53 wild-type). TP53 mutations, two of which were novel: c.826_830delCCTGT and c.475_476GC>TT, were identified in 44% of the cases. Mutations in KRAS, HRAS, and PIK3CA were identified in two, two and four cases, respectively. None of the effusions analysed showed NRAS or BRAF mutations. The aCGH analysis revealed highly imbalanced genomes similar to those described in primary ovarian carcinomas. No specific profile was indicated to distinguish tumors with TP53 mutations from those without. The molecular profiling of cells found in effusion fluids from patients with ovarian cancer thus showed considerable molecular heterogeneity. TP53 seems to be the most frequently mutated gene in these cells and may serve a leading role in the metastatic process.

Microarray analysis of cumulus cells in women with ovarian endometriosis undergoing intracytoplasmic sperm injection

Objective:

The aim of this study was to find the significantly altered genes in cumulus cells of women with ovarian endometriosis by using microarray and quantitative polymerase chain reaction analysis.

Methods:

Thirty women with ovarian endometriosis and 30 age–body mass index matched controls (women with infertility as a result of pure male factor) were enrolled in this study. Cumulus cells from study participants who underwent controlled ovarian hyperstimulation were isolated mechanically. Microarray comparative genomic hybridization was used to compare the transcriptome of cumulus cells from women with ovarian endometriosis and controls. According to the different expression levels in the microarrays and their putative functions, KRAS, ZNF322, and SDHA were selected and analyzed by real-time quantitative polymerase chain reaction.

Results:

There was no significant difference in the basal conditions between patients with endometriosis and controls, such as age, body mass index, basal follicle stimulating hormone and estradiol levels, and total gonadotrophin dosage. The gene expression profile of cumulus cells from patients with endometriosis was significantly different from that of controls. A total of 295 genes were significantly up- or down-regulated (p-value < 0.05 and absolute fold change > 1.5). For all of the genes adjusted p-value was found to be 0.999. Polymerase chain reaction analysis showed that KRAS and ZNF322 mRNA levels in the cumulus cells of patients with ovarian endometriosis were significantly up-regulated compared to controls (fold changes: 3.05 and 3.22, respectively).

Conclusion:

KRAS and ZNF322 mRNA levels in the cumulus cells of patients with ovarian endometriosis were significantly up-regulated.

Activation of STAT3 and STAT5 Signaling in Epithelial Ovarian Cancer Progression: Mechanism and Therapeutic Opportunity

Epithelial ovarian cancer (EOC) is the most lethal of all gynecologic malignancies. Despite advances in surgical and chemotherapeutic options, most patients with advanced EOC have a relapse within three years of diagnosis. Unfortunately, recurrent disease is generally not curable. Recent advances in maintenance therapy with anti-angiogenic agents or Poly ADP-ribose polymerase (PARP) inhibitors provided a substantial benefit concerning progression-free survival among certain women with advanced EOC. However, effective treatment options remain limited in most recurrent cases. Therefore, validated novel molecular therapeutic targets remain urgently needed in the management of EOC. Signal transducer and activator of transcription-3 (STAT3) and STAT5 are aberrantly activated through tyrosine phosphorylation in a wide variety of cancer types, including EOC. Extrinsic tumor microenvironmental factors in EOC, such as inflammatory cytokines, growth factors, hormones, and oxidative stress, can activate STAT3 and STAT5 through different mechanisms. Persistently activated STAT3 and, to some extent, STAT5 increase EOC tumor cell proliferation, survival, self-renewal, angiogenesis, metastasis, and chemoresistance while suppressing anti-tumor immunity. By doing so, the STAT3 and STAT5 activation in EOC controls properties of both tumor cells and their microenvironment, driving multiple distinct functions during EOC progression. Clinically, increasing evidence indicates that the activation of the STAT3/STAT5 pathway has significant correlation with reduced survival of recurrent EOC, suggesting the importance of STAT3/STAT5 as potential therapeutic targets for cancer therapy. This review summarizes the distinct role of STAT3 and STAT5 activities in the progression of EOC and discusses the emerging therapies specifically targeting STAT3 and STAT5 signaling in this disease setting.

Targeted sequencing of a specific gene panel detects a high frequency of ARID1A and PIK3CA mutations in ovarian clear cell carcinoma

BACKGROUND

The objective of this study was to assess the mutational profile in epithelial ovarian cancer using formalin-fixed, paraffin-embedded (FFPE) tumor specimens from a Taiwanese population by performing targeted sequencing of 9 cancer-associated genes.

METHODS

Targeted sequencing was performed on 32 formalin-fixed, paraffin embedded (FFPE) tumor specimens, consisting of matched samples from 16 epithelial ovarian cancer patients. Genetic alterations in the 9 cancer-associated genes were detected using a deep sequencing (>1000×) approach.

RESULTS

ARID1A and PIK3CA were the most frequently mutated genes. Specifically, ARID1A mutations and PIK3CA mutations were detected in 77.8% and 66.7% of ovarian clear cell carcinoma patients, respectively. Mutations in other genes, including MLH1 (6.3%) and CREBBP (6.3%), were detected in the Taiwanese population. We also identified coexisting ARID1A-PIK3CA mutations (43.8%) and ARID1A-KRAS mutations (12.5%) in tumors. It should also be noted that we identified the presence of three coexisting mutations, the ARID1A-KRAS-PIK3CA mutations and the ARID1A-CREBBP-PIK3CA mutations.

CONCLUSIONS

In summary, we identified novel genetic alterations in patients with epithelial ovarian carcinoma (EOC) in a Taiwanese populations. Further studies are needed to elucidate the mechanism of chromatin remodeling to examine the role of the PI3K/AKT pathway, to determine the critical roles of these mechanisms in tumor development and the progression of ovarian malignancy and to investigate new targeted therapies. Overall, our findings were reliable and are worthy of further study.

Multipoint Kras oncogene mutations potentially indicate mucinous carcinoma on the entire spectrum of mucinous ovarian neoplasms

Kras mutation is a common phenomenon in many human neoplasms. We aimed to assess the Kras mutational status along the histological continuum from normal ovaries to the development of benign, borderline and malignant ovarian mucinous neoplasms. We analyzed 41 cases of malignant, 10 cases of borderline, 7 cases of benign mucinous ovarian tumors and 7 cases of normal ovarian tissue. The prevalence of Kras mutations in the normal ovary was 0.00% (n=0/7), while the prevalence in benign, borderline and malignant mucinous neoplasms was 57.14% (n=4/7), 90.00% (n=9/10) and 75.61% (n=31/41), respectively. Multiple Kras mutations were detected in 6 cases of mucinous carcinoma, including 5 double mutations with G13D/V14I (n=1), G12V/G13S (n=1), G12D/G13S (n=3) and one triple mutation with A11V/G13N/V14I (n=1). We identified six cases with 3 novel Kras mutations not previously described in the COSMIC database, which included A11V (n=3) and V14I (n=2) in mucinous carcinomas, and A11T (n=1) in a mucinous borderline tumor. In conclusion, Kras mutation appears to be one of the imperative events in the ovarian mucinous adenoma–borderline tumor–carcinoma sequence, as increased numbers of Kras mutations have been shown to be the strongest predictor of unequivocal malignancy in ovarian mucinous neoplasms.

First-in-Class ERK1/2 Inhibitor Ulixertinib (BVD-523) in Patients with MAPK Mutant Advanced Solid Tumors: Results of a Phase I Dose-Escalation and Expansion Study

Ulixertinib (BVD-523) is an ERK1/2 kinase inhibitor with potent preclinical activity in BRAF- and RAS-mutant cell lines. In this multicenter phase I trial (NCT01781429), 135 patients were enrolled to an accelerated 3 + 3 dose-escalation cohort and six distinct dose-expansion cohorts. Dose escalation included 27 patients, dosed from 10 to 900 mg twice daily and established the recommended phase II dose (RP2D) of 600 mg twice daily. Ulixertinib exposure was dose proportional to the RP2D, which provided near-complete inhibition of ERK activity in whole blood. In the 108-patient expansion cohort, 32% of patients required dose reduction. The most common treatment-related adverse events were diarrhea (48%), fatigue (42%), nausea (41%), and dermatitis acneiform (31%). Partial responses were seen in 3 of 18 (17%) patients dosed at or above maximum tolerated dose and in 11 of 81 (14%) evaluable patients in dose expansion. Responses occurred in patients with NRAS-, BRAF V600-, and non-V600 BRAF-mutant solid tumors.Significance: Here, we describe the first-in-human dose-escalation study of an ERK1/2 inhibitor for the treatment of patients with advanced solid tumors. Ulixertinib has an acceptable safety profile with favorable pharmacokinetics and has shown early evidence of clinical activity in NRAS- and BRAF V600- and non-V600-mutant solid-tumor malignancies. Cancer Discov; 8(2); 184-95. ©2017 AACR.See related commentary by Smalley and Smalley, p. 140This article is highlighted in the In This Issue feature, p. 127.

Preoperative HE4, CA125 and ROMA in the differential diagnosis of benign and malignant adnexal masses

Background

The aim of this study was to evaluate HE4, CA125 and ROMA in the preoperative differentiation benign ovarian diseases from epithelial ovarian cancer depending on the menopausal status.

Methods

In order to estimate markers’ concentrations in the serum of women with benign ovarian disease (n = 128) and with epithelial ovarian carcinoma (n = 96) the electrochemiluminescence (ECLIA) technique has been applied.

Results

Using the ROC analysis, although no statistical differences were found among their AUCs, the ROMA algorithm seems to be effective in gathering the diverse performance of HE4 and CA125. The AUC for HE4, CA125 and ROMA for all patients were: 0.895; 0.879 and 0.918, respectively. At established new optimal cutoff values for HE4, CA125 and ROMA we found higher specificity in postmenopausal compared to premenopausal women (96.9 vs 89.8 % and 97.7 vs 84.1 % and 95.9 vs 89.1 %, respectively). The sensitivity of HE4 in pre- and postmenopausal women was similar (83.5 vs 83.8 %), while for CA125 was the highest in premenopausal women (87.0 vs 84.1 %). For HE4, CA125 and ROMA the negative predictive value was high (97.6, 93.9 and 94.4 %, respectively).

Conclusions

The ROMA algorithm shows the best diagnostic performance to distinguish epithelial ovarian cancer from benign ovarian disease. We found the high specificity of HE4 and CA125 while differentiating ovarian benign diseases from epithelial ovarian cancer in postmenopausal women and the high sensitivity of CA125 in detecting epithelial ovarian cancer in premenopausal patients.

Molecular differences in the KRAS gene mutation between a primary tumor and related metastatic sites - case report and a literature review

In recent years the the set of diagnostic tools in colorectal cancers has been extended by the assessment of the KRAS gene status. Currently it is a necessary step in order to qualify patients for the targeted therapy. The results of the analysis of several studies revealed a high rate of compliance of the KRAS gene mutational status in primary and metastatic tumors. In this paper we present a rare case of incompatibility of the KRAS mutations in the primary tumor located in the colon and metastatic changes in the liver.

An integrative approach to identifying cancer chemoresistance-associated pathways

Background

Resistance to chemotherapy severely limits the effectiveness of chemotherapy drugs in treating cancer. Still, the mechanisms and critical pathways that contribute to chemotherapy resistance are relatively unknown. This study elucidates the chemoresistance-associated pathways retrieved from the integrated biological interaction networks and identifies signature genes relevant for chemotherapy resistance.

Methods

An integrated network was constructed by collecting multiple metabolic interactions from public databases and the k-shortest path algorithm was implemented to identify chemoresistant related pathways. The identified pathways were then scored using differential expression values from microarray data in chemosensitive and chemoresistant ovarian and lung cancers. Finally, another pathway database, Reactome, was used to evaluate the significance of genes within each filtered pathway based on topological characteristics.

Results

By this method, we discovered pathways specific to chemoresistance. Many of these pathways were consistent with or supported by known involvement in chemotherapy. Experimental results also indicated that integration of pathway structure information with gene differential expression analysis can identify dissimilar modes of gene reactions between chemosensitivity and chemoresistance. Several identified pathways can increase the development of chemotherapeutic resistance and the predicted signature genes are involved in drug resistant during chemotherapy. In particular, we observed that some genes were key factors for joining two or more metabolic pathways and passing down signals, which may be potential key targets for treatment.

Conclusions

This study is expected to identify targets for chemoresistant issues and highlights the interconnectivity of chemoresistant mechanisms. The experimental results not only offer insights into the mode of biological action of drug resistance but also provide information on potential key targets (new biological hypothesis) for further drug-development efforts.

Circulating free DNA and p53 antibodies in plasma of patients with ovarian epithelial cancers

BACKGROUND

This study was conducted in order to evaluate the significance of circulating free DNA (CFDNA), blood plasma p53 antibodies (p53-Ab) and mutations of KRAS gene in the prognosis of ovarian epithelial cancers.

PATIENTS AND METHODS

A total of 126 patients were included in this study. KRAS mutations and CFDNA were detected by means of the PCR-restriction fragment length polymorphism (PCR-RFLP) and enriched by the PCR-RFLP method. Enzyme-linked immunosorbent assay was used to analyze plasma p53-Ab.

RESULTS

KRAS mutations were detected in 27 (21.4%) of examined tumors. The frequency of KRAS mutations was especially high in mucinous cancers (P < 0.001). CFDNA and p53-Ab were frequently detected in patients with serous cancers in high grade (P < 0.001). The overall survival rate was significantly lower for patients with serous tumors and CFDNA and p53-Ab-positive than negative tumors (P = 0.022 and P < 0.001, respectively). In mucinous ovarian cancer, a worse overall survival was correlated with the KRAS mutations (P = 0.03).

CONCLUSIONS

The results of the present study suggested that a presence of KRAS mutations in mucinous ovarian cancer and CFDNA and p53-Ab in serous tumors was correlated with the highest risk of cancer progression.

PAR-4 as a possible new target for pancreatic cancer therapy

IMPORTANCE OF THE FIELD

Pancreatic cancer (PC) is a deadly disease that is intractable to currently available treatment regimens. Although well described in different tumors types, the importance of apoptosis inducer prostate apoptosis response-4 (Par-4) in PC has not been appreciated. PC is an oncogenic kras driven disease, which is known to downregulate Par-4. Therefore, this review highlights its significance and builds a strong case supporting the role of Par-4 as a possible therapeutic target in PC.

AREAS COVERED IN THIS REVIEW

Literature-based evidence spanning the last 15 years on Par-4 and its significance in PC.

WHAT THE READER WILL GAIN

This review provides comprehensive knowledge of the significance of Par-4 and its association with kras status in PC, along with the crosstalk with crucial resistance and survival molecules NF-kappaB and Bcl-2 that ultimately are responsible for the overall poor outcome of different therapeutic approaches in this disease.

TAKE HOME MESSAGE

Par-4 holds promise as a potential therapeutic target that can be induced by chemopreventive agents and small-molecule inhibitors either alone or in combination with standard chemotherapeutics leading to selective apoptosis in PC cells. It also acts as a chemosensitizer and therefore warrants further clinical investigations in this disease.