PAX8 is a novel marker for differentiating between various types of tumor, particularly ovarian epithelial carcinomas

PAX8 expression in cancerous and non-neoplastic tissue: a tissue microarray study on more than 17,000 tumors from 149 different tumor entities

PAX8 plays a role in development of the thyroid, kidney, and the Wolffian and Mullerian tract. In surgical pathology, PAX8 immunohistochemistry is used to determine tumors of renal and ovarian origin, but data on its expression in other tumors are conflicting. To evaluate PAX8 expression in normal and tumor tissues, a tissue microarray containing 17,386 samples from 149 different tumor types and 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. PAX8 results were compared with previously collected data on cadherin 16 (CDH16). PAX8 positivity was found in 40 different tumor types. The highest rate of PAX8 positivity was found in thyroidal neoplasms of follicular origin (98.6-100%), gynecological carcinomas (up to 100%), renal tumors (82.6-97.8%), and urothelial neoplasms (2.3-23.7%). Important tumors with near complete absence of PAX8 staining (< 1%) included all subtypes of breast cancers, hepatocellular carcinomas, gastric, prostatic, pancreatic, and pulmonary adenocarcinomas, neuroendocrine neoplasms, small cell carcinomas of various sites, and lymphomas. High PAX8 expression was associated with low tumor grade in 365 non-invasive papillary urothelial carcinomas (p < 0.0001) but unrelated to patient outcome and/or tumor phenotype in clear cell renal cell carcinoma, high-grade serous ovarian cancer, and endometrioid endometrial carcinoma. For determining a renal tumor origin, sensitivity was 88.1% and specificity 87.2% for PAX8, while sensitivity was 85.3% and specificity 95.7% for CDH16. The combination of PAX8 and CDH16 increased specificity to 96.8%. In conclusion, PAX8 immunohistochemistry is a suitable diagnostic tool. The combination of PAX8 and CDH16 positivity has high specificity for renal cell carcinoma.

Invasive Ductal Breast Carcinoma Metastasis to the Uterine Cervix Presenting As Heavy Vaginal Bleeding: A Case Report and a Literature Review

Breast carcinoma metastasis to the uterine cervix is a rare occurrence with diagnostic intricacies. We present a case of a 38-year-old woman diagnosed with bilateral stages IIIA and IIIB invasive ductal carcinoma of the breast who developed heavy vaginal bleeding post-treatment, revealing metastatic involvement of the cervix, confirmed by CT imaging and pathological examination, as the presenting sign of widely metastatic disease. This case underscores the importance of a thorough review of systems and physical exams as well as considering uncommon metastatic sites in breast cancer patients.

An Unlikely Source of Iodine Uptake: A Bronchogenic Cyst Masquerading as Metastatic Thyroid Cancer

Radioactive iodine therapy and posttreatment scanning are essential components of differentiated thyroid carcinoma treatment and detection of metastatic disease. False-positive results can be seen on an I-131 scan and are important for clinicians to be aware of. Here, we present a case of a 33-year-old female with follicular thyroid carcinoma who was noted to have an area of moderate uptake in the chest on a whole-body scan following remnant ablation with 30 mCi of I-131 (1.11GBq) concerning for a metastatic hilar lymph node. This was determined to be a mediastinal bronchogenic cyst on surgical pathology. It has been previously proposed that the expression of sodium iodide symporters in some bronchogenic cysts could be the mechanism by which iodine uptake is seen within them. We were able to demonstrate positive immunohistochemical staining for both sodium iodide symporter and the associated paired box gene 8 transcription factor in the cyst sample, which supports the proposed theory.

MYC is sufficient to generate mid-life high-grade serous ovarian and uterine serous carcinomas in a p53-R270H mouse model

Genetically engineered mouse models (GEMM) have fundamentally changed how ovarian cancer etiology, early detection, and treatment is understood. However, previous GEMMs of high-grade serous ovarian cancer (HGSOC) have had to utilize genetics rarely or never found in human HGSOC to yield ovarian cancer within the lifespan of a mouse. MYC, an oncogene, is amongst the most amplified genes in HGSOC, but it has not previously been utilized to drive HGSOC GEMMs. We coupled Myc and dominant negative mutant p53-R270H with a fallopian tube epithelium-specific promoter Ovgp1 to generate a new GEMM of HGSOC. Female mice developed lethal cancer at an average of 15.1 months. Histopathological examination of mice revealed HGSOC characteristics including nuclear p53 and nuclear MYC in clusters of cells within the fallopian tube epithelium and ovarian surface epithelium. Unexpectedly, nuclear p53 and MYC clustered cell expression was also identified in the uterine luminal epithelium, possibly from intraepithelial metastasis from the fallopian tube epithelium (FTE). Extracted tumor cells exhibited strong loss of heterozygosity at the p53 locus, leaving the mutant allele. Copy number alterations in these cancer cells were prevalent, disrupting a large fraction of genes. Transcriptome profiles most closely matched human HGSOC and serous endometrial cancer. Taken together, these results demonstrate the Myc and Trp53-R270H transgene was able to recapitulate many phenotypic hallmarks of HGSOC through the utilization of strictly human-mimetic genetic hallmarks of HGSOC. This new mouse model enables further exploration of ovarian cancer pathogenesis, particularly in the 50% of HGSOC which lack homology directed repair mutations. Histological and transcriptomic findings are consistent with the hypothesis that uterine serous cancer may originate from the fallopian tube epithelium.

Two Cases of Biphasic Synovial Sarcoma With Expression of PAX8 and ER: A Diagnostic Pitfall

Synovial sarcoma (SS) is a high-grade malignant neoplasm frequently arising in the deep soft tissue of the lower and upper extremities of young adults. Primary SS in the pelvis is extremely rare with scattered case reports. It often causes a diagnostic challenge in small biopsy and/or with aberrant expression of immunohistochemical markers. Here, we report 2 unusual cases of SS in the pelvis. Microscopically both cases present with biphasic morphology including spindle and epithelioid cells. In addition, the tumor cells in both cases expressed PAX8 and estrogen receptor. PAX8 is a transcription factor usually expressed in tumors of thyroid gland, kidney, and Müllerian system origin. The expression of PAX8 especially with co-expression of estrogen receptor can be misleading and result in a diagnosis of Müllerian tumors in female patients with pelvic masses. The diagnosis of SS for both cases was confirmed either with the fluorescence in situ hybridization or reverse transcription polymerase chain reaction showing a SS18 (SYT) (18q11) gene rearrangement. It is imperative to include SS in the differential diagnosis for malignant neoplasms exhibiting monotonous spindle cells (monophasic SS) and biphasic mixed monotonous spindle and epithelioid tumor cells in female patients with a pelvic mass. Molecular study for SS18 translocation is essential for the diagnosis in such cases.

Aberrant transcription factors in the cancers of the pancreas

Transcription factors (TFs) are essential for proper activation of gene set during the process of organogenesis, differentiation, lineage specificity. Reactivation or dysregulation of TFs regulatory networks could lead to deformation of organs, diseases including various malignancies. Currently, understanding the mechanism of oncogenesis became necessity for the development of targeted therapeutic strategy for different cancer types. It is evident that many TFs go awry in cancers of the pancreas such as pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine neoplasms (PanNENs). These mutated or dysregulated TFs abnormally controls various signaling pathways in PDAC and PanNENs including RTK, PI3K-PTEN-AKT-mTOR, JNK, TGF-β/SMAD, WNT/β-catenin, SHH, NOTCH and VEGF which in turn regulate different hallmarks of cancer. Aberrant regulation of such pathways have been linked to the initiation, progression, metastasis, and resistance in pancreatic cancer. As of today, a number of TFs has been identified as crucial regulators of pancreatic cancer and a handful of them shown to have potential as therapeutic targets in pre-clinical and clinical settings. In this review, we have summarized the current knowledge on the role and therapeutic usefulness of TFs in PDAC and PanNENs.

Establishment of a piglet model for peritoneal metastasis of ovarian cancer

Background

A piglet model for peritoneal metastasis (PM) of ovarian cancer was developed. It will contribute to establishing innovative chemotherapeutical and surgical strategies without any limitation on rodent models.

Methods

A total of 12 four- to five-week-old piglets of 7 to 8 kg were used. Two phases of ovarian cancer cell injections were performed with laparoscopic surgery.

In phase I trial, 5.0 × 10⁶ SK-OV-3 cells in 0.1 ml suspension were inoculated into the omentum, peritoneum, and uterine horns of two piglets twice with a one-week interval. In the phase II trial, 5.0 × 10⁶ SNU-008 cells in 0.1 ml suspension were injected only into uterine horns within the same time frame because tumor implantation after inoculation of SK-OV-3 cells was not observed at the omentum or peritoneum in the phase I trial. Modified peritoneal cancer index (PCI) score was used to monitor tumorigenesis up to 4 weeks after inoculation. Tumor tissues disseminated in the peritoneum 4 weeks after injection were used for histological examination with hematoxylin and eosin (H&E) and paired-box gene 8 (PAX-8) staining.

Results

In the phase I trial, two piglets showed PM with modified PCI scores of 5 and 4 at 3 weeks after the first inoculation, which increased to 14 and 15 after 4 weeks, respectively. In the phase II trial, PM was detected in eight of ten piglets, which showed modified PCI scores of 6 to 12 at 4 weeks after the first inoculation. The overall incidence of PM from the total of 12 piglets after inoculation was 75%. Immunohistochemical H&E and PAX-8 staining confirmed metastatic tumors.

Conclusions

This study provides strong evidence that piglets can be employed as a model for PM by inoculating ovarian cancer cell lines from humans. Using two cell lines, the PM rate is 75%.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03533-1.

Primary Fallopian Tube Carcinoma Presenting with a Massive Inguinal Tumor: A Case Report and Literature Review

Primary fallopian tube carcinoma (PFTC) has characteristics similar to those of ovarian carcinoma. The typical course of PFTC metastasis includes peritoneal dissemination and pelvic and paraaortic lymph node metastasis, while inguinal lymph node metastasis is rare. Moreover, the initial presentation of PFTC with an inguinal tumor is extremely rare. A 77-year-old postmenopausal woman presented with a massive 12-cm inguinal subcutaneous tumor. After tumor resection, histopathological and immunohistochemical analysis showed that the tumor was a high-grade serous carcinoma of gynecological origin. Subsequent surgery for total hysterectomy with bilateral salpingo-oophorectomy revealed that the tumor developed in the fallopian tube. She received adjuvant chemotherapy with carboplatin and paclitaxel, followed by maintenance therapy with niraparib. There has been no recurrence or metastasis 9 months after the second surgery. We reviewed the literature for cases of PFTC and ovarian carcinoma that initially presented with an inguinal tumor. In compliance with the Preferred Reporting Items for Systematic Reviews guidelines, a systematic literature search was performed through 31 January 2022 using the PubMed and Google scholar databases and identified 14 cases. In half of them, it was difficult to identify the primary site using preoperative imaging modalities. Disease recurrence occurred in two cases; thus, the prognosis of this type of PFTC appears to be good.

PAX-8 Expression in Salivary Duct Carcinoma

Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma resembling breast ductal carcinoma. It accounts for ~10% of malignant tumors of the salivary glands. Most cases show expression of CK7 and androgen receptor. PAX-8 is a transcription factor, with expression reported in renal, Müllerian, and thyroid carcinomas. Previous studies have described an absence of PAX-8 immunostaining in most primary salivary gland neoplasms, including SDCs. However, PAX-8 expression is frequently found in neoplasms that can metastasize to salivary glands, suggesting the possibility that this protein can be used to differentiate SDC from secondary neoplastic involvement of the salivary gland. We evaluated the expression of PAX-8 in 14 cases of SDC from our institution. One case showed diffuse moderate to strong PAX-8 positivity, while 2 tumors showed focal weak staining. Therefore, we conclude that although the majority of SDC are negative for PAX-8, rare diffuse positivity can be seen in these primary salivary gland tumors. This could potentially pose difficulty in ruling out metastatic disease from another PAX-8-positive primary neoplasm.

Paired-Box Gene 8 (PAX8) and Its Association With Epithelial Carcinomas

Cancer is the second most common culprit of mortality in the United States and epithelial carcinomas are considered as one of the most predominant types of cancer. The association between epithelial cancers and paired-box gene 8 (PAX8) has been studied significantly before. PAX8 belongs to the paired-box gene family, which plays an important role in the organogenesis of different body organ systems, especially the thyroid gland, the renal system, and the Müllerian system. Immunohistochemical staining is being used to detect PAX8 expression in different epithelial cancers and differentiate them from PAX8-negative tumors. In follicular, papillary, and anaplastic thyroid carcinomas, targeting the PAX8/peroxisome proliferator-activated receptors (PPARs) fusion protein is being considered as a potential mechanism for therapy. Moreover, because of its high expression in primary ovarian cancers, PAX8 is being considered as a target for ovarian cancer treatment as well. More studies are needed to test the possibility of using PAX8 as a possible target for managing endometrial carcinomas. In this article, we review the functions of the PAX8 gene, how its mutations lead to the development of certain epithelial carcinomas, how it can be used as a diagnostic or a prognostic marker, and its potential as a therapeutic target for these cancers.

Overlapping Immunohistochemical Features of Adenocarcinoma of the Nonpigmented Ciliary Body Epithelium and Renal Cell Carcinoma

PURPOSE

To find immunohistochemical markers that distinguish adenocarcinoma of the nonpigmented ciliary epithelium (NPCE) from metastatic carcinoma, especially metastatic renal cell carcinoma.

DESIGN

Retrospective case series.

METHODS

Three cases of adenocarcinoma of the NPCE were examined histologically with hematoxylin-eosin stain and immunohistochemical stains including vimentin, AE1/AE3, Cam 5.2, CK7, PAX2, PAX8, AMACR, and CAIX. We also reviewed previously reported cases of this tumor.

RESULTS

We found that the immunohistochemical profile of adenocarcinoma of the NPCE can overlap with renal cell carcinoma. Both tumors can express vimentin, cytokeratin AE1/AE3, Cam 5.2, PAX2, PAX8, and AMACR. One of the adenocarcinomas of the NPCE in our series also expressed CD10 and the renal cell carcinoma marker (RCC Ma). Carbonic anhydrase IX (CAIX) was not detected in any of the 3 tumors.

CONCLUSIONS

Adenocarcinomas arising in phthisic eyes can be diagnostically challenging. We have found it particularly difficult to distinguish adenocarcinoma of the NPCE from metastatic carcinoma, especially metastatic clear cell renal cell carcinoma and papillary renal cell carcinoma. Because of the immunophenotypic overlap, most patients will require systemic workup including imaging of the kidneys to be certain of the diagnosis.

Incidental Detection of Ovarian Cancer as a Solitary Peridiaphragmatic Distant Lymph Node Metastasis without Pelvic Lesions on 18F-FDG PET/CT

The spreading pattern of ovarian carcinoma is unique and unlike most other cancers, because exfoliated ovarian cancer cells primarily disseminate within the abdominal cavity, which are then transported throughout the peritoneum by physiological peritoneal fluid. An initial manifestation of a solitary peridiaphragmatic distant metastatic lymph node without peritoneal involvement is very rare. This study reports a case with an incidentally found single hypermetabolic mass in the peridiaphragmatic space without a pelvic lesion in the baseline staging ¹⁸ F-FDG PET/CT that histologically turned out to be metastatic serous papillary carcinoma due to ovarian cancer. ¹⁸F-FDG PET/CT may allow the identification of the initial manifestation of unexpected distant oligometastatic statuses of an unknown primary ovarian cancer.

Current Achievements and Applications of Transcriptomics in Personalized Cancer Medicine

Over the last decades, transcriptome profiling emerged as one of the most powerful approaches in oncology, providing prognostic and predictive utility for cancer management. The development of novel technologies, such as revolutionary next-generation sequencing, enables the identification of cancer biomarkers, gene signatures, and their aberrant expression affecting oncogenesis, as well as the discovery of molecular targets for anticancer therapies. Transcriptomics contribute to a change in the holistic understanding of cancer, from histopathological and organic to molecular classifications, opening a more personalized perspective for tumor diagnostics and therapy. The further advancement on transcriptome profiling may allow standardization and cost reduction of its analysis, which will be the next step for transcriptomics to become a canon of contemporary cancer medicine.

High grade, advanced, serous ovarian cancer with low serum CA125 levels

This study compares characteristics of advanced stage, high grade serous ovarian cancer, presenting with high or low serum CA125 level. This was a retrospective cohort of 118 patients with high grade serous ovarian, fallopian tube or primary peritoneal cancer, stages IIIC-IV diagnosed from January 1 1997 through January 9 2017. Patient demographics, tumour characteristics, surgical findings, chemotherapy protocols and clinical outcomes were collected. Three groups were evaluated: group A: 21 patients with CA125 serum level ≤152 U/ml, group B: 97 patients with CA125 serum level >152 U/ml, group C: 43 patients from group B with CA125 serum level >500 U/ml and <1000 U/ml. No significant difference was found between groups regarding age, stage at diagnosis, extent of residual disease or disease volume. More group A patients had surgery as primary treatment compared to groups B and C (p=.003, p=.022, respectively). CA125 level at recurrence was lower in group A as compared to the other groups (162.2 vs. 851.7 and 603.4, p=.003, p=.006). Overall survival and progression-free survival did not differ based on CA125 levels. We conclude that patients with advanced stage, high grade, serous ovarian cancer with low CA125 serum levels had the same clinical outcome as patients with higher levels.Impact StatementWhat is already known on this subject? It is known that CA125 level is a prognostic and predictive factor for epithelial ovarian cancer (EOC) outcome. It is elevated in 80% of the patients and within normal range in only 10% of women with advanced stage EOC. Various studies had addressed the patients with advanced stage serous EOC who had high serum CA125 levels at time of diagnosis. But, no study has addressed the 10% of patients with advanced stage who had low serum CA125 levels at time of diagnosis.What the results of this study add? To the best of our knowledge, this is the first study addressing patients with advanced stage EOC who had low serum CA125 levels at time of diagnosis. According to the results of this study, patients with advanced stage, high grade serous EOC presenting with low serum CA125 levels have similar clinical outcomes as do patients with high serum CA125 levels.What the implications are of these findings for clinical practice and/or further research? Further translational research is encouraged for this group of tumours to identify specific molecular markers that might lead to better understanding and treatment for the disease.

PAX8, an Emerging Player in Ovarian Cancer

Ovarian Cancer is one of the most lethal and widespread gynecological malignancies. It is the seventh leading cause of all cancer deaths worldwide. High-Grade Serous Cancer (HGSC), the most commonly occurring subtype, alone contributes to 70% of all ovarian cancer deaths. This is mainly attributed to the complete lack of symptoms during the early stages of the disease and absence of an early diagnostic marker.PAX8 is emerging as an important histological marker for most of the epithelial ovarian cancers, as it is expressed in about 90% of malignant ovarian cancers, specifically in HGSC. PAX8 is a member of the Paired-Box gene family (PAX1-9) of transcription factors whose expression is tightly controlled temporally and spatially. The PAX genes are well known for their role in embryonic development and their expression continues to persist in some adult tissues. PAX8 is required for the normal development of Müllerian duct that includes Fallopian tube, uterus, cervix, and upper part of vagina. In adults, it is expressed in the Fallopian tube and uterine epithelium and not in the ovarian epithelium. Considering the recent studies that predict the events preceding the tumorigenesis of HGSC from the Fallopian tube, PAX8 appears to have an important role in the development of ovarian cancer.In this chapter, we review some of the published findings to highlight the significance of PAX8 as an important marker and an emerging player in the pathogenesis of ovarian cancer. We also discuss regarding the future perspectives of PAX8 wherein it could contribute to the betterment of ovarian cancer diagnosis and treatment.

Evaluation of paraneoplastic antigens reveals TRIM21 autoantibodies as biomarker for early detection of ovarian cancer in combination with autoantibodies to NY-ESO-1 and TP53

BACKGROUND

The majority of ovarian cancer cases are diagnosed at an advanced stage with poor prognosis. This study evaluates autoantibodies against tumor antigens to identify candidate biomarkers for early detection of ovarian cancer in women at increased risk.

OBJECTIVE

To assess the immunoreactivity of paraneoplastic antigens and tumor associated antigens with high-grade serous ovarian cancer (HGSOC) samples.

METHODS

Five paraneoplastic antigens along with three tumor-associated antigens were evaluated with HGSOC patient serum samples. Validation screening was performed with n= 164 serum samples consisting of: 50 late stage HGSOC, 14 early stage HGSOC, 50 benign ovarian cyst, and 50 healthy control samples on ELISA and western blot. The four markers TRIM21, NY-ESO-1, TP53, and PAX8 were evaluated on a second validation serum set, n= 150.

RESULTS

TRIM21 achieved the highest sensitivity in the first validation screening of 33% with 100% specificity. Combining TRIM21 with NY-ESO-1, TP53, and PAX8 provided 67% sensitivity with 94% specificity, and 56% sensitivity at 98% specificity. These four markers resulted in 46% sensitivity with 98% specificity in the second validation cohort; TRIM21 achieved the highest individual sensitivity of 36%.

CONCLUSIONS

Autoantibodies to TRIM21, NY-ESO-1, and TP53 may complement CA125 in screening of women at genetic risk for ovarian cancer.

Anaplastic thyroid carcinoma: Updates on WHO classification, clinicopathological features and staging

Anaplastic thyroid carcinoma is an uncommon carcinoma representing 1 to 4% of all thyroid cancers. The carcinoma is most common in females of the eight decades. It is a locally advanced cancer with frequent infiltration of surrounding organs, blood vessels and skin of neck. Paraneoplastic manifestations could occur. Approximately half of the patients with anaplastic thyroid carcinoma had distant metastasis with lung and brain as the most frequent sites of metastasis. The median survival of patients with anaplastic thyroid carcinoma reported was from 1 to 6 months. The terminology of the cancer in World Health Organization is "anaplastic thyroid carcinoma" rather than "undifferentiated thyroid carcinoma". In the latest American Joint Committee on Cancer (AJCC) TNM staging system for anaplastic thyroid carcinoma, there are updates on T and N categories. To conclude, updated knowledge of clinicopathological features, classification, pathological staging will improve our understanding of the cancer and will help in the management of the patients with this aggressive cancer.

Echoendoscopic appearance of mediastinal metastasis from papillary renal carcinoma

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is being increasingly used in the diagnostic workup of mediastinal diseases. Here, we report a patient with cystic lesions located in the mediastinum, the sampling of which facilitated the diagnosis of renal neoplasm. This paper confirms the usefulness and safety of EBUS/TBNA on cystic lesions and describes a rare presentation of intrathoracic metastases from carcinoma of the kidney.

Oncogenic properties and signaling basis of the PAX8-GLIS3 fusion gene

Hyalinizing trabecular tumors of the thyroid are rare and mostly benign epithelial neoplasms of follicular cell origin, which have recently been shown to be underpinned by the PAX8-GLIS3 fusion gene. In our study, we sought to investigate the potential oncogenic mechanisms of the PAX8-GLIS3 fusion gene. Forced expression of PAX8-GLIS3 was found to increase proliferation, clonogenic potential and migration of human nonmalignant thyroid (Nthy-ori 3-1) and embryonic kidney (HEK-293) cells. Moreover, in xenografts, Nthy-ori 3-1 PAX8-GLIS3 expressing cells generated significantly larger and more proliferative tumors compared to controls. These oncogenic effects were found to be mediated through activation of the Sonic Hedgehog (SHH) pathway. Targeting of smoothened (SMO), a key protein in the SHH pathway, using the small molecule inhibitor Cyclopamine partially reversed the increased proliferation, colony formation and migration in PAX8-GLIS3 expressing cells. Our data demonstrate that the oncogenic effects of the PAX8-GLIS3 fusion gene are, at least in part, due to an increased activation of the SHH pathway.

Metastatic clear cell renal cell carcinoma in isolated retroperitoneal lymph node without evidence of primary tumor in kidneys: A case report

BACKGROUND

Retroperitoneal lymph node dissection (RPLND) plays a diagnostic, therapeutic, and prognostic role in myriad urologic malignancies, including testicular carcinoma, renal cell carcinoma (RCC), and upper urinary tract urothelial carcinoma. RCC represents 2% of all cancers with approximately 25% of patients presenting with advanced disease. Clear cell RCC (CCRCC) is the most common RCC, accounting for 75%-80% of all RCC.

CASE SUMMARY

A 71-year-old man presented with a history of benign prostatic hypertrophy. He was asymptomatic without any hematuria, pain, or other urinary symptoms. A computed tomography (CT) scan of the abdomen and pelvis showed a 1.8 cm left retroperitoneal lymph node. There was no evidence of renal pathology. A core biopsy was performed of the left para-aortic lymph node. Although the primary tumor site was unknown, the morphological and immunohistochemical features were most consistent with CCRCC. A RPLND was performed which revealed a single mass 5.5 cm in greatest dimension with extensive necrosis. The retroperitoneal lymph node was most compatible with CCRCC. A nephrectomy was not conducted as a renal mass had not been detected on any prior imaging studies. The patient did not receive any type of adjuvant therapy. The patient underwent surveillance with serial CT scans with contrast of the chest, abdomen, and pelvis for the next 5 years, all of which demonstrated no recurrent or metastatic disease and no evidence of retroperitoneal adenopathy.

CONCLUSION

Our unique case emphasizes the therapeutic role of metastasectomy in metastatic CCRCC even in the absence of primary tumor in the kidneys.

PAX8 expression in high-grade serous ovarian cancer positively regulates attachment to ECM via Integrin β3

Background

Ovarian cancer is the third most common cause of death among gynecologic malignancies worldwide. Understanding the biology and molecular pathogenesis of ovarian epithelial tumors is key to developing improved prognostic indicators and effective therapies. We aimed to determine the effects of PAX8 expression on the migrative, adhesive and survival capabilities of high-grade serous carcinoma cells.

Methods

PAX8 depleted Fallopian tube secretory cells and ovarian cancer cells were generated using short interfering siRNA. Anoikis resistance, cell migration and adhesion properties of PAX8 silenced cells were analyzed by means of specific assays. Chromatin immunoprecipitation (ChIP) was carried out using a PAX8 polyclonal antibody to demonstrate that PAX8 is able to bind to the 5′-flanking region of the ITGB3 gene positively regulating its expression.

Results

Here, we report that RNAi silencing of PAX8 sensitizes non-adherent cancer cells to anoikis and affects their tumorigenic properties. We show that PAX8 plays a critical role in migration and adhesion of both Fallopian tube secretory epithelial cells and ovarian cancer cells. Inhibition of PAX8 gene expression reduces the ability of ovarian cancer cells to migrate and adhere to the ECM and specifically to fibronectin and/or collagen substrates. Moreover, loss of PAX8 strongly reduces ITGB3 expression and consequently the correct expression of the αvβ3 heterodimer on the plasma membrane.

Conclusions

Our results demonstrate that PAX8 modulates the interaction of tumor cells with the extracellular matrix (ECM). Notably, we also highlight a novel pathway downstream this transcription factor. Overall, PAX8 could be a potential therapeutic target for high-grade serous carcinoma.

MSK2 promotes proliferation and tumor formation in squamous cervical cancer via PAX8/RB-E2F1/cyclin A2 axis

Patients with cervical cancer have abnormal cell proliferation and invasion after many years of latency. However, the precise mechanisms remain unclear. Mitogen- and stress-activated kinase 2 (MSK2) is a serine/threonine kinase which displays a phenotype that promotes tumor growth and metastasis in many different types of tumors. The aim of the present study was to determine the effects of MSK2 on the proliferation of cervical cancer cells and elucidate the signaling pathways through which MSK2 exerts its effects in the pathogenesis of squamous cell carcinoma (SCC). Our results confirmed that MSK2 expression was significantly upregulated in cervical cancer cells both in vivo and in vitro. We further found that the expression patterns of paired-box gene 8 (PAX8) and MSK2 were positively correlated in cervical cancer specimens. Moreover, MSK2 knockdown inhibited the phosphorylation of PAX8 and retinoblastoma protein (RB), and suppressed the sequential expressions of cell proliferation factors E2F1 and cyclin A2, resulting in the inhibition of SCC cell proliferation and tumor formation. Thus, this study demonstrates that MSK2 has oncogenic effects in the formation and development of SCC via the PAX8/RB-E2F1/cyclin A2 axis.

Synchronous Ovarian and Breast Cancers with a Novel Variant in BRCA2 Gene: A Case Report

We report a case of a 52-year-old female with a family history of pancreatic and colon cancers who presented with a right breast mass positive for high-grade medullar carcinoma with triple-negative biomolecular profile. Further workup was performed finding a left ovarian mass. The patient underwent laparotomy performing optimal cytoreduction on bilateral ovarian tumors; the pathology and immunohistochemistry confirmed bilateral ovary adenocarcinoma with positive peritoneal malignancy. Due to her synchronic breast and ovarian cancers, a genetic profile was performed detecting a new pathogenic variant in the BRCA2 gene: c.3606_3607del (p.Ser1203Cysfs). She was given chemotherapy with carboplatin and paclitaxel obtaining complete clinical response. Regarding her breast cancer, she had a right modified radical mastectomy and prophylactic left mastectomy obtaining complete clinical response. This case presents with an unusual subtype and difficult histologic diagnosis of a synchronic medullar breast cancer and ovary carcinoma associated with a new mutation of the BRCA2 gene.

Utility of monoclonal PAX8 antibody for distinguishing intrathyroid thymic carcinoma from follicular cell-derived thyroid carcinoma

Follicular cell-derived thyroid carcinomas, including thyroid squamous cell carcinomas (SCCs) and anaplastic carcinomas, are immunoreactive for paired-box gene 8 (PAX8), while non-follicular cell-derived thyroid carcinomas stain negative for the PAX8 antibody. Intrathyroid thymic carcinoma (ITTC) arising from the intrathyroidal ectopic thymus exhibits moderate-to-strong nuclear reactivity for polyclonal PAX8. This is difficult to understand given that PAX8 is not associated with embryonic thymic development. We aimed to determine the diagnostic significance of monoclonal PAX8 antibody in distinguishing ITTCs from follicular cell-derived thyroid carcinomas. Ten ITTCs, 14 poorly differentiated thyroid carcinomas (PDTCs), 14 thyroid SCCs, 7 thymic tissue specimens, 7 thymomas, and 1 thymic carcinoma were analyzed using antibodies against polyclonal and monoclonal PAX8, thyroid transcription factor-1, p63, and CD5. Four ITTCs (40.0%) stained positive for polyclonal PAX8; none stained positive for monoclonal PAX8. All PDTCs and 92.9% of SCCs were immunoreactive for both polyclonal and monoclonal PAX8. All PDTCs, 46.2% of SCCs, and none of the ITTCs were immunoreactive for thyroid transcription factor-1. Eight ITTCs (80.0%), but none of the PDTCs and SCCs, were immunoreactive for CD5. We are the first to show that ITTCs stain negative for monoclonal PAX8. Monoclonal PAX8 is a more reliable marker than polyclonal PAX8 for determining follicular cell origin. We conclude that monoclonal PAX8 is a useful marker for distinguishing ITTCs from PDTCs and SCCs. Monoclonal PAX8 negativity is additional evidence in support of ITTCs not being follicular cell-derived thyroid carcinomas, but having a thymic origin.

C/EBPβ enhances platinum resistance of ovarian cancer cells by reprogramming H3K79 methylation

Chemoresistance is a major unmet clinical obstacle in ovarian cancer treatment. Epigenetics plays a pivotal role in regulating the malignant phenotype, and has the potential in developing therapeutically valuable targets that improve the dismal outcome of this disease. Here we show that a series of transcription factors, including C/EBPβ, GCM1, and GATA1, could act as potential modulators of histone methylation in tumor cells. Of note, C/EBPβ, an independent prognostic factor for patients with ovarian cancer, mediates an important mechanism through which epigenetic enzyme modifies groups of functionally related genes in a context-dependent manner. By recruiting the methyltransferase DOT1L, C/EBPβ can maintain an open chromatin state by H3K79 methylation of multiple drug-resistance genes, thereby augmenting the chemoresistance of tumor cells. Therefore, we propose a new path against cancer epigenetics in which identifying and targeting the key regulators of epigenetics such as C/EBPβ may provide more precise therapeutic options in ovarian cancer.

In ovarian cancer, the mechanism of chemoresistance is a key question. Here, the authors demonstrate that C/EBPβ and DOT1L together increase methylation of H3K79, which upregulates expression of oncogenic genes and drives poor platinum response and poor survival in ovarian cancer.

PRKCI promotes immune suppression in ovarian cancer

Here, Sarkar et al. report that PRKCI expression, which is a key feature of high-grade serous ovarian carcinoma (HGSOC), is also up-regulated in serous tubal intraepithelial carcinoma (STIC) and early fallopian tube (FT) lesions. Using a transgenic mouse model of ovarian cancer overexpressing PRKCI, they show that PRKCI is a deregulated ovarian cancer-specific oncogene and plays a role in early stages of cancer development.

A key feature of high-grade serous ovarian carcinoma (HGSOC) is frequent amplification of the 3q26 locus harboring PRKC-ι (PRKCI). Here, we show that PRKCI is also expressed in early fallopian tube lesions, called serous tubal intraepithelial carcinoma. Transgenic mouse studies establish PRKCI as an ovarian cancer-specific oncogene. Mechanistically, we show that the oncogenic activity of PRKCI relates in part to the up-regulation of TNFα to promote an immune-suppressive tumor microenvironment characterized by an abundance of myeloid-derived suppressor cells and inhibition of cytotoxic T-cell infiltration. Furthermore, system-level and functional analyses identify YAP1 as a downstream effector in tumor progression. In human ovarian cancers, high PRKCI expression also correlates with high expression of TNFα and YAP1 and low infiltration of cytotoxic T cells. The PRKCI–YAP1 regulation of the tumor immunity provides a therapeutic strategy for highly lethal ovarian cancer.

RNA-seq analysis identifies key long non-coding RNAs connected to the pathogenesis of alcohol-associated head and neck squamous cell carcinoma

Alcohol consumption has been implicated in the pathogenesis of head and neck squamous cell carcinoma (HNSCC), although its mechanism is poorly understood. Recent advances in the identification and understanding of long non-coding RNAs (lncRNAs) have indicated that these molecules have a profound effect on numerous biological processes, including tumorigenesis and oncogenesis. The present authors hypothesize that alcohol-mediated dysregulation of lncRNAs is a key event in HNSCC pathogenesis. An in silico differential expression analysis utilizing RNA sequencing (RNA-seq) data from 34 HNSCC patients, which included alcohol drinkers and non-alcohol drinkers, identified a panel of lncRNAs that were dysregulated due to alcohol consumption. Normal oral keratinocytes were then exposed to ethanol and acetaldehyde to validate the RNA-seq results. Two lncRNAs that were differentially expressed due to alcohol consumption were identified from RNA-seq analysis of the clinical data: lnc-PSD4-1 and lnc-NETO-1. Oral keratinocytes exposed to alcohol and acetaldehyde demonstrated dysregulation of these two lncRNAs, thus validating the results of RNA-seq analysis. In addition, low expression of the lnc-PSD4-1 isoform, lnc-PSD4-1:14, exhibited a strong correlation with high survival rates in a Cox proportional hazards regression model. Therefore, these lncRNAs may play a key role in the early pathogenesis of HNSCC, since they are dysregulated in both clinical data and in vitro experiments mimicking the effects of alcohol use.

Unusual presentation of metastatic ovarian carcinoma as an enlarged intramammary lymph node

Metastasis to the breast most commonly arises from a contralateral primary breast malignancy; however, metastatic disease can also result from extramammary malignancies by hematogenous or lymphatic dissemination. This case report reviews an unusual presentation of primary ovarian carcinoma with metastasis to an intramammary lymph node.

Merkel cell carcinoma - recent advances in the biology, diagnostics and treatment

Merkel cell carcinoma (MCC) is an uncommon primary cutaneous carcinoma with neuroendocrine differentiation. Since recent discovery of MCCs strong association with Merkel cell polyomavirus (MCPyV), there has been a rapid increase in the understanding of the carcinomas genetics, molecular biology and pathogenesis. In our study, we reviewed recent advances and controversies concerning MCC histogenesis, epidemiology, diagnostic and prognostic markers. We analyzed the association of MCPyV with MCC and the possible new targets for therapy. We also examined English-based literature regarding MCC pathogenesis published between 2008 and 2013, which lead to a deeper understanding of the topic. Our study showed that the association of MCPyV strongly influences the course of MCC. Additionally, it has been shown that a immunological response to MCPyV may in the future give hope to identify new therapeutic strategies in treatment of this fatal malignancy. This article is part of a Directed Issue entitled: Rare Cancers.

The relationship between DNA methylation, genetic and expression inter-individual variation in untransformed human fibroblasts

BACKGROUND

DNA methylation plays an essential role in the regulation of gene expression. While its presence near the transcription start site of a gene has been associated with reduced expression, the variation in methylation levels across individuals, its environmental or genetic causes, and its association with gene expression remain poorly understood.

RESULTS

We report the joint analysis of sequence variants, gene expression and DNA methylation in primary fibroblast samples derived from a set of 62 unrelated individuals. Approximately 2% of the most variable CpG sites are mappable in cis to sequence variation, usually within 5 kb. Via eQTL analysis with microarray data combined with mapping of allelic expression regions, we obtained a set of 2,770 regions mappable in cis to sequence variation. In 9.5% of these expressed regions, an associated SNP was also a methylation QTL. Methylation and gene expression are often correlated without direct discernible involvement of sequence variation, but not always in the expected direction of negative for promoter CpGs and positive for gene-body CpGs. Population-level correlation between methylation and expression is strongest in a subset of developmentally significant genes, including all four HOX clusters. The presence and sign of this correlation are best predicted using specific chromatin marks rather than position of the CpG site with respect to the gene.

CONCLUSIONS

Our results indicate a wide variety of relationships between gene expression, DNA methylation and sequence variation in untransformed adult human fibroblasts, with considerable involvement of chromatin features and some discernible involvement of sequence variation.