Detection of loss of heterozygosity at chromosome 3p25-26 in primary and metastatic ovarian clear-cell carcinoma: utilization of microdissection and polymerase chain reaction in archival tissues

Targeting DNA Damage Response Pathway in Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is one of the major types of ovarian cancer and is of higher relative prevalence in Asians. It also shows higher possibility of resistance to cisplatin-based chemotherapy leading to poor prognosis. This may be attributed to the relative lack of mutations and aberrations in homologous recombination-associated genes, which are crucial in DNA damage response (DDR), such as BRCA1, BRCA2, p53, RAD51, and genes in the Fanconi anemia pathway. On the other hand, OCCC is characterized by a number of genetic defects rendering it vulnerable to DDR-targeting therapy, which is emerging as a potent treatment strategy for various cancer types. Mutations of ARID1A, PIK3CA, PTEN, and catenin beta 1 (CTNNB1), as well as overexpression of transcription factor hepatocyte nuclear factor-1β (HNF-1β), and microsatellite instability are common in OCCC. Of particular note is the loss-of-function mutations in ARID1A, which is found in approximately 50% of OCCC. ARID1A is crucial for processing of DNA double-strand break (DSB) and for sustaining DNA damage signaling, rendering ARID1A-deficient cells prone to impaired DNA damage checkpoint regulation and hence sensitive to poly ADP ribose polymerase (PARP) inhibitors. However, while preclinical studies have demonstrated the possibility to exploit DDR deficiency in OCCC for therapeutic purpose, progress in clinical application is lagging. In this review, we will recapitulate the preclinical studies supporting the potential of DDR targeting in OCCC treatment, with emphasis on the role of ARID1A in DDR. Companion diagnostic tests (CDx) for predicting susceptibility to PARP inhibitors are rapidly being developed for solid tumors including ovarian cancers and may readily be applicable on OCCC. The potential of various available DDR-targeting drugs for treating OCCC by drawing analogies with other solid tumors sharing similar genetic characteristics with OCCC will also be discussed.

Rethinking of treatment strategies and clinical management in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC), with unique clinical and molecular characteristics compared with other histological types of epithelial ovarian cancer (EOC), behaves like a distinct entity and has a poorer prognosis than other EOC types, especially in advanced stages. In addition, OCCC comprises approximately 27% of all EOC cases in Japan, compared with 12% in Western countries. Historically, patients with OCCC have been eligible for chemotherapeutic and surgical trials of EOC. It has been difficult to evaluate the specific impact of these trials on the prognosis of women with OCCC because of its rarity and unique molecular characteristics. Recent studies of OCCC revealed significant molecular variations related to carcinogenesis and molecular targets that could directly facilitate patient stratification and subsequent precision medicine. Thus, treatment strategies specific for OCCC based on its clinical and molecular characteristics are urgently needed. In this review, we highlight the management and treatment of OCCC from clinical aspects.

A phase II evaluation of sunitinib in the treatment of persistent or recurrent clear cell ovarian carcinoma: An NRG Oncology/Gynecologic Oncology Group Study (GOG-254)

OBJECTIVES

To determine the efficacy and tolerability of sunitinib in recurrent or persistent clear cell ovarian cancer patients.

METHODS

All patients had one or two prior regimens with measurable disease. Tumors were at least 50% clear cell histomorphology and negative for WT-1 antigen and estrogen receptor expression by immunohistochemistry. Sunitinib 50 mg per day for 4 weeks was administered in repeated 6-week cycles until disease progression or prohibitive toxicity. Primary end points were progression-free survival (PFS) at 6 months and clinical response. The study was designed to determine if the drug had a response rate of at least 20% or 6-month PFS of at least 25%.

RESULTS

Of 35 patients enrolled, 30 were treated and eligible (median age: 51, range: 27-73). Twenty-five (83%) were White, 4 (13%) Asian, and 1 (3%) unknown. The majority 28 (83%) patients, underwent ≤3 but 2 (7%) had 16 courses of study therapy. Five (16.7%) patients had PFS ≥6 months (90% CI: 6.8%-31.9%). Two (6.7%) patients had a partial or complete response (90% CI: 1.2%-19.5%). The median PFS was 2.7 months. The median overall survival was 12.8 months. The most common grade 3 adverse events were fatigue (4), hypertension (4), neutropenia (4), anemia (3), abdominal pain (3), and leukopenia (3). Grade 4-5 adverse events included: thrombocytopenia (5), anemia (2), acute kidney Injury (1), stroke (1), and allergic reaction (1).

CONCLUSION

Sunitinib demonstrated minimal activity in the second- and third-line treatment of persistent or recurrent clear cell ovarian carcinoma. ClinicalTrials.gov number, NCT00979992.

Updates and emerging therapies for rare epithelial ovarian cancers: one size no longer fits all

Epithelial ovarian carcinoma consists of not one, but several, entities. A number of subtypes exist, including high-grade and low-grade serous carcinomas, clear cell, endometrioid carcinoma and mucinous carcinoma. Historically, women with epithelial ovarian cancer have been treated similarly and "lumped" in the same cooperative group treatment trials, irrespective of their tumor subtype. Recently, however, differences in epidemiology, tumor biology, tumor marker expression and treatment responses have been elucidated among the histologic subtypes, with a clear distinction emerging between the Type I, lower grade tumors and Type 2, higher grade epithelial malignancies. A mounting body of research demonstrates that a "one-size-fits-all" treatment approach to epithelial ovarian tumors is no longer relevant, especially for the Type I subtypes. Indeed, with the exception of high-grade serous carcinoma, most other epithelial subtypes exhibit some degree of chemotherapy resistance, rendering treatment problematic, especially in the setting of advanced disease. This review summarizes the genetic, molecular, and clinical differences of the more rare, but clinically important, Type I epithelial ovarian tumors. Additionally, a critical appraisal of both historical and contemporary treatment approaches and the rationale for targeted therapies are emphasized.

Alterations of Hypoxia-Induced Factor Signaling Pathway Due to Mammalian Target of Rapamycin (mTOR) Suppression in Ovarian Clear Cell Adenocarcinoma: In Vivo and in Vitro Explorations for Clinical Trial

Objectives

Before setting into the clinical trial using a combination of mammalian target of rapamycin (mTOR) inhibitors (rapamycin and everolimus) and other anticancer drugs, this study was conducted to confirm the efficacy of the new therapeutic strategy for ovarian clear cell adenocarcinoma (CCA), which targeted mTOR–hypoxia-induced factor (HIF) signal transduction system.

Materials and Methods

Using the cultured cells of CCA and animal models, alteration of mTOR-HIF cofactors and cell proliferation under the mTOR inhibitor–treated condition were analyzed.

Results

Mammalian target of rapamycin–HIF cofactors were inhibited dependent on concentration by mTOR inhibitor, resulting in suppression of the cultured CCA proliferation. However, von Hippel-Lindau was up-regulated at the messenger RNA level. In the nude mice with subcutaneously implanted CCA cells, apoptosis and necrosis were detected especially around the center of the tumors in the mTOR inhibitor–treated group more conspicuously than in the nontreated group. In the assessment of combination therapy with other antitumor agents, a combined treatment with mTOR inhibitor and chemotherapeutic agents caused a significant decrease in tumor size compared to the chemotherapeutic agents–only group.

Conclusions

Treatment by mTOR inhibitor is expected to down-regulate the cell proliferation of the CCA as a new therapeutic strategy.

Aberrant expression of the mammalian target of rapamycin, hypoxia-inducible factor-1α, and glucose transporter 1 in the development of ovarian clear-cell adenocarcinoma

Ovarian clear-cell adenocarcinoma (CCA) is known to be a type of cancer in humans with a high frequency of expression of the mammalian target of rapamycin (mTOR), hypoxia-inducible factor-1 (HIF-1), and glucose transporter 1 (Glut1). In this study, we aimed to determine how these alterations contribute to tumor development of CCAs. Immunohistochemical expressions of phosphorylated-mTOR (p-mTOR), HIF-1α, and Glut1 were analyzed in 36 CCAs and 60 coexistent putative precursor lesions: 19 nonatypical and 16 atypical endometriotic lesions, and 11 benign and 14 borderline clear-cell adenofibroma (CCAF) components. Twenty-one cases with solitary endometriosis were also examined. The frequencies of immunopositivity for p-mTOR (in cytoplasm or nucleus), HIF-1α (in nucleus), and Glut1 increased in accordance with higher cytological atypia in the putative precursors: 58%, 5%, and 16% in the nonatypical endometriosis; 63%, 37%, and 50% in the atypical endometriosis; 77%, 95%, and 95% in the endometriosis-associated CCAs; 27%, 0%, and 0% in the benign-CCAF components; 64%, 79%, and 43% in the borderline CCAF components; and 71%, 100%, and 93% in the CCAF-associated CCAs, respectively. p-mTOR, HIF-1α (in the nucleus), and Glut1 were positive in 10%, 5%, and 19% of the solitary endometriosis, respectively. In the putative precursor lesions coexisting with CCA, a strong correlation in the expression between p-mTOR and HIF-1α and between HIF-1α and Glut1 was identified. Expressions of p-mTOR, HIF-1α, and Glut1 have already been evident in the putative precursor lesions of CCA, and these alterations cumulatively occur in the development of ovarian CCA.

Sorafenib efficacy in ovarian clear cell carcinoma revealed by transcriptome profiling

The purpose of this study was to investigate a new modality of therapy against ovarian clear cell carcinoma (OCCC), a chemoresistant subtype of ovarian cancer. Microarray datasets of ovarian cancer cell lines and cancer tissues were analyzed using bioinformatic tools. The gene expression profile of OCCC was similar to that of renal cell carcinoma (RCC). This similarity was at least partially due to hepatocyte nuclear factor 1 pathway activation common to both malignancies. In addition, oncogenic pathway alterations were characteristic of OCCC including hypoxia inducible factor 1 alpha subunit and relatively high Ras activities. Therefore, we predicted that the multi-kinase inhibitor sorafenib, which is approved for RCC and suppresses Ras activity, would also be effective against OCCC. Orally administered sorafenib (40 mg/kg per day) significantly inhibited tumor growth in nude mice when it was given after inoculation with the OCCC cell line RMG-2 (P = 0.002). Furthermore, sorafenib significantly reduced tumor size when it was administered to established RMG-2 tumors (P = 0.0002), while intraperitoneal injection of cisplatin (5 mg/kg per week) did not. In conclusion, the prominent anti-tumor effect of sorafenib against OCCC indicates that sorafenib is a promising candidate drug and supports the need for clinical trials using sorafenib against OCCC. This report demonstrates a method to utilize genome-wide information to facilitate translational research for treatments against less common subtypes of cancers.

An allelotype analysis indicating the presence of two distinct ovarian clear-cell carcinogenic pathways: endometriosis-associated pathway vs. clear-cell adenofibroma-associated pathway

Patterns of allele loss (loss of heterozygosity (LOH)) were studied to identify the genetic backgrounds underlying the two putative carcinogenic pathways of ovarian clear-cell adenocarcinoma: carcinomas thought to arise in endometriosis (endometriosis-associated carcinomas, 20 cases) and carcinomas thought to be derived from clear-cell adenofibroma ((CCAF)-associated carcinomas, 14 cases). Each tumor was assessed for LOH at 24 polymorphic loci located on 12 chromosomal arms: 1p, 3p, 5q, 8p, 9p, 10q, 11q, 13q, 17p, 17q, 19p, and 22q. For all informative loci, the frequency of LOH was not statistically different between the two carcinoma groups: 38% (66/172 loci) in the endometriosis-associated carcinomas and 35% (40/113 loci) in the CCAF-associated carcinomas. In the endometriosis-associated carcinomas, LOH was detected at high frequencies (>50%) at 3p, 5q, and 11q and at low frequencies (<20%) at 8p, 13q, and 17p. In the CCAF-associated carcinomas, LOH was detected at high frequencies at 1p, 10q, and 13q and at low frequencies at 3p, 9p, 11q, and 17q. The frequencies of LOH at chromosomes 3p, 5q, and 11q were significantly higher in the endometriosis-associated carcinomas than in the CCAF-associated carcinomas (P = 0.026, 0.007, and 0.011, respectively). Immunohistochemical analysis demonstrated a close association between the allelic status of the 3p25-26 locus and levels of von Hippel-Lindau (VHL) protein expression (P = 0.0026). These data further support the presence of two distinct carcinogenic pathways to ovarian clear-cell adenocarcinoma; the allelic status of the 3p, 5q, and 11q loci may provide a means to identify the precursor lesions of these carcinomas.

Differential subcellular localisation of the tumour suppressor protein LIMD1 in breast cancer correlates with patient survival

The tumour suppressor gene (TSG) LIM domain containing protein 1 (LIMD1) has been associated with transformation of epithelial cells of the lung and its expression is downregulated in all lung tumour samples tested compared to normal lung matched controls. In the first study of its kind we used an anti-LIMD1 specific monoclonal antibody to investigate expression/localisation of the LIMD1 protein in a well-characterised tissue microarray of breast cancers and normal adjacent epithelia. Comparison of tumour with adjacent normal and distant normal tissue demonstrated that LIMD1 expression is moderate to high compared to tumour. There was also a significant correlation with histological grade (p = 0.0001), tumour size (p = 0.013) and tumour type (p = 0.004) indicating an association with aggressive disease. Cytoplasmic LIMD1 expression was seen in 99.3% of cases, with 43.1% showing both nuclear and cytoplasmic localisation. Absence/loss of nuclear staining showed a strong correlation with patient survival and was indicative of poor prognosis (p = 0.033). There was no association with lymph node status and other clinicopathological parameters. Nuclear staining was more pronounced in better prognosis tumours and normal tissue. This study demonstrates that LIMD1 represents a novel prognostic marker for breast cancer. Combined with the fact that LIMD1 expression is downregulated in lung cancers this clearly indicates that LIMD1 may represent a critical TSG, the function of which is deregulated via overall loss of expression and/or relocalisation within the cell during tumour development. The possible functions of LIMD1 localisation within the nucleus and cytoplasm and its relationship to tumour prognosis are discussed.

Loss of heterozygosity (LOH) on chromosomes 2q, 3p and 21q in Indian oral squamous cell carcinoma

Around the world, 200,000 people a year are affected by oral cancer, and the incidence of this disease is 10 times higher in India than Japan, mainly due to the custom of chewing tobacco. Loss of heterozygosity (LOH) on the long arm of chromosome 2 (2q), the short arm of chromosome 3 (3p) and the long arm of chromosome 21 (21q) are observed in several human cancers. We identified novel tumor suppressor loci on these regions in primary oral squamous cell carcinomas (OSCCs) in Japanese. However, there has been no detailed analysis of LOH on these chromosomes in Indians. In the present study, we investigated LOH at 2q, 3p and 21q using 9 microsatellite markers in 26 Indian OSCCs. LOH was detected in 25 (96.2%) out of 26 informative samples at one or more of the loci examined. On the basis of the results, two commonly deleted regions were identified and a detailed deletion map was constructed. In the first region, a high frequency of LOH was observed at the D3S1007 locus (53.8%) on 3p25, which is located in the region neighboring the VHL (von Hippel-Lindau) gene. In the second region, LOH was concentrated at the D3S966 locus (50.0%) on 3p21.3, suggesting the presence of a putative tumor suppressor gene (TSG) associated with OSCCs. These results strongly suggest that there are at least two candidate TSGs located on chromosome 3p, and that alteration in them is associated with the tumorigenesis of OSCCs.

Human kidney injury molecule-1 (hKIM-1): a useful immunohistochemical marker for diagnosing renal cell carcinoma and ovarian clear cell carcinoma

Human kidney injury molecule-1 (hKIM-1), a type I transmembrane glycoprotein expressed in injured renal proximal tubules, was also found in renal cell carcinoma (RCC). The current study attempts to evaluate the diagnostic utility of hKIM-1 in a large series of 480 neoplasms including defined subtypes of renal cell tumors, metastatic RCCs, and nonrenal tumors. Tissue microarray (TMA) sections containing 179 renal cell tumors (73 clear cell RCC, 30 papillary RCC, 16 chromophobe RCC, 15 oncocytoma, and 45 metastatic RCC) were included in this study. In addition, 80 cases of renal cell neoplasm and 221 nonrenal tumors in routine tissue sections were also included. Both TMA and routine sections were incubated with anti-hKIM-1 monoclonal antibody using an EnVision-HRP kit. The results demonstrated that a membranous/cytoplasmic staining pattern for hKIM-1 was observed in 54 of 73 (74%) clear cell RCCs and 28 of 30 (93%) papillary RCCs on TMA sections. Zero of 54 chromophobe RCCs and 4 of 41 (9.75%) oncocytomas were positive for hKIM-1 when combining TMA and routine sections. Similar staining results were observed in 35 of 45 (78%) metastatic RCCs. Data from cDNA microarray expression and Western blot demonstrated similar findings. Fifteen of 16 cases (93.8%) of clear cell carcinoma of the ovary demonstrated positive reactivity for hKIM-1. These data indicate that hKIM-1: (1) is a relatively sensitive and specific marker for papillary, clear cell, and metastatic RCCs, (2) can be used to distinguish clear cell from chromophobe RCC, and (3) may serve as a diagnostic marker for clear cell carcinoma of the ovary.

Expression and regulation of tumor necrosis factor alpha in normal and malignant ovarian epithelium

Epidemiologic studies implicate inflammatory stimuli in the development of ovarian cancer. The proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) and both its receptors (TNFRI and TNFRII) are expressed in biopsies of this malignancy. Here, we tested the hypothesis that TNF-alpha is a regulator of the proinflammatory microenvironment of ovarian cancer. A cancer profiling array showed higher expression of TNF-alpha in ovarian tumors compared with normal ovarian tissue, and cultured ovarian cancer cells expressed up to 1,000 times more TNF-alpha mRNA than cultured normal ovarian surface epithelial cells; TNF-alpha protein was only detected in the supernatant of tumor cell cultures. Treatment with TNF-alpha induced TNF-alpha mRNA via TNFRI in both malignant and normal cells with evidence for enhanced TNF-alpha mRNA stability in tumor cells. TNF-alpha induced TNF-alpha protein in an autocrine fashion in tumor but not in normal ovarian surface epithelial cells. The TNF-alpha neutralizing antibody infliximab reduced the constitutive levels of TNF-alpha mRNA in tumor cell lines capable of autocrine TNF-alpha production. Apart from TNF-alpha mRNA expression, several other proinflammatory cytokines were constitutively expressed in malignant and normal ovarian surface epithelial cells, including interleukin (IL)-1alpha, IL-6, CCL2, CXCL8, and M-CSF. TNF-alpha treatment further induced these cytokines with de novo transcription of IL-6 mRNA contrasting with the increased stability of CCL2 mRNA. RNA interference directed against TNF-alpha was highly effective in abolishing constitutive IL-6 production by ovarian tumor cells. In summary, we show that TNF-alpha is differentially regulated in ovarian cancer cells compared with untransformed cells and modulates production of several cytokines that may promote ovarian tumorigenesis. Infliximab treatment may have a role in suppressing the TNF-alpha-driven inflammatory response associated with ovarian cancer.

3p21.3 tumor suppressor cluster: prospects for translational applications

Chromosomal abnormalities at the 3p21.3 region, including homozygous deletions and loss of heterozygosity and expressional deficiencies in 3p21.3 genes including transcriptional silences by promoter hypermethylation, altered mRNA splicing and aberrant transcripts, and lost or defect protein translation and post-translational modifications, are frequently found in most human cancers. Inactivation of 3p21.3 genes in primary tumors affects a wide spectrum of key biological processes such as cell proliferation, cell cycle kinetics, signaling transduction, ion exchange and transportation, apoptosis and cell death, and demonstrates the molecular signatures of carcinogenesis. Restoration of defective 3p21.3 genes with several wild-type 3p21.3 genes suppresses tumor cell growth both in vitro and in vivo. These findings suggest several 3p21.3 genes as potential tumor suppressors and implicates these 3p21.3 genes for future development as biomarkers for the early detection and diagnosis of cancer, and as prognostic and therapeutic tools for cancer prevention and molecular cancer therapy.

Epithelial cancer in Fanconi anemia complementation group D2 (Fancd2) knockout mice

Fanconi anemia (FA) is a genetic disorder characterized by hypersensitivity to DNA damage, bone marrow failure, congenital defects, and cancer. To further investigate the in vivo function of the FA pathway, mice with a targeted deletion in the distally acting FA gene Fancd2 were created. Similar to human FA patients and other FA mouse models, Fancd2 mutant mice exhibited cellular sensitivity to DNA interstrand cross-links and germ cell loss. In addition, chromosome mispairing was seen in male meiosis. However, Fancd2 mutant mice also displayed phenotypes not observed in other mice with disruptions of proximal FA genes. These include microphthalmia, perinatal lethality, and epithelial cancers, similar to mice with Brca2/Fancd1 hypomorphic mutations. These additional phenotypes were not caused by defects in the ATM-mediated S-phase checkpoint, which was intact in primary Fancd2 mutant fibroblasts. The phenotypic overlap between Fancd2-null and Brca2/Fancd1 hypomorphic mice is consistent with a common function for both proteins in the same pathway, regulating genomic stability.

Immunocytochemistry versus molecular fingerprinting of metastases

Examination of cytological samples of cancer to suggest a possible primary site of origin is one of the commonest and most difficult tasks of diagnostic cytopathologists. Currently, both cytomorphology and immunocytochemistry are the main approaches to this diagnostic dilemma. We report the application of microsatellite analysis in cytological samples in a patient with a primary colonic tumour and two subsequent lung nodules, which were suspected on CT scans of the chest, and compared the findings with those obtained with conventional immunocytochemistry. The molecular results were in agreement with the radiological impression and conflicted with the immunocytochemistry. We conclude that immunocytochemical and molecular biology approaches to the diagnosis of tumours may give rise to contradictory results.

Identification, genomic organization and mRNA expression of CRELD1, the founding member of a unique family of matricellular proteins

We have isolated and characterized a unique gene that encodes a highly conserved membrane bound extracellular protein that defines a new epidermal growth factor-related gene family. The CRELD1 (Cysteine-Rich with EGF-Like Domains 1) gene (previously known as cirrin) was cloned from a human chromosome 3 BAC. Mapping of the gene confirmed its position at chromosome 3p25.3. The gene is ubiquitously expressed in early development and later becomes more markedly expressed in the developing heart, limb buds, mandible and central nervous system. Expression persists in adulthood in most tissues. Sequence analysis suggests that this is a cell adhesion protein. The mouse orthologue was cloned and mapped to the syntenic region of mouse chromosome 6. Orthologues or homologues have also been identified for cow, Chinese hamster, Drosophila and Caenorhabditis elegans. The CRELD1 gene is deleted in the human cytogenetic disorder 3p- syndrome and is in the region of loss of heterozygosity for several types of cancer. A potential role for this protein in these disorders is discussed.