Mucinous tumours of the ovary—primary and metastatic

Organoids From Mucinous Appendiceal Adenocarcinomas as High-Fidelity Models for Individual Therapy

Background

Mucinous appendiceal adenocarcinoma (MAA) is a rare, heterogeneous disease. Patients with unrespectable mucinous appendiceal adenocarcinoma presenting with peritoneal spread are treated by intraperitoneal chemotherapy, hyperthermic intraperitoneal chemotherapy, systemic chemotherapy, or targeted therapy. However, there are no guidelines for efficacious drugs against mucinous appendiceal adenocarcinoma. Therefore, relevant high-fidelity models should be investigated to identify effective drugs for individual therapy.

Methods

Surgical tumor specimens were obtained from a mucinous appendiceal adenocarcinoma patient. The tissue was digested and organoid culture was established. H&E and immunohistochemistry staining as well as DNA sequencing was performed on tissue and organoid. The pathological characteristics and gene mutations of the organoid were compared to those of the original tumor. Drug sensitivity tests were performed on organoid and the patient clinical responds to chemotherapy and targeted therapy was compared.

Results

Organoids were successfully established and stably passaged. Pathological characteristics of organoids including H&E staining and expression of protein markers (CK20, CDX-2, STAB2, CD7, PAX8) were consistent to those of the original tumor. Moreover, the organoids carried the same gene mutations as the primary tumor. Sensitivity of the organoids to chemotherapeutic drugs and tyrosine kinase inhibitors included: 5-FU (IC₅₀ 43.95 μM), Oxaliplatin (IC₅₀ 23.49 μM), SN38 (IC₅₀ 1.02 μM), Apatinib (IC₅₀ 0.10 μM), Dasatinib (IC₅₀ 2.27 μM), Docetaxel (IC₅₀ 5.26 μM), Regorafenib (IC₅₀ 18.90 μM), and Everolimus (IC₅₀ 9.20 μM). The sensitivities of organoid to these drugs were comparable to those of the patient's clinical responses.

Conclusion

The mucinous appendiceal adenocarcinoma organoid model which retained the characteristics of the primary tumor was successfully established. Combined organoid-based drug screening and high throughput sequencing provided a promising way for mucinous appendiceal adenocarcinoma treatment.

The utility of PAX8 and SATB2 immunohistochemical stains in distinguishing ovarian mucinous neoplasms from colonic and appendiceal mucinous neoplasm

Objectives

It is challenging to distinguish between primary ovarian mucinous tumors and metastatic mucinous neoplasms from the lower gastrointestinal tract, including appendiceal tumors. A combination of PAX8 and SATB2 immunohistochemical stains can be used as a diagnostic tool to distinguish between these cases.

Results

Immunostaining for SATB2, PAX8, CK7, CK20 and CDX2 was performed on 50 ovarian mucinous neoplasms (OMN) (39 cystadenomas, 4 borderline and 7 adenocarcinomas), 63 mucinous colorectal carcinoma (CRC), and 9 appendiceal mucinous neoplasms (AMN) [8 low grade appendiceal mucinous neoplasms (LAMN) and 1 adenocarcinoma]. PAX8 was positive in 32% of OMN and negative in all CRC and AMN cases. SATB2 was expressed in 2.0% of OMN, 77.8% of AMN, and 49.2% of CRC cases. CK7 was positive in 78.0% of OMN, 33.3% of AMN, and 9.5% of CRC cases. CK20 was expressed in 24.0% of OMN, 88.9% of OMN, and 87.3% of CRC cases. CDX2 was positive in 14.0% of OMN, 100% of AMN, and 90.5% of CRC cases. PAX8 can differentiate between OMN and AMN with high specificity but low sensitivity. CDX2 is the most sensitive marker for CRC and AMN, whereas SATB2 has better specificity.

SATB2 is a supportive marker for the differentiation of a primary mucinous tumor of the ovary and an ovarian metastasis of a low-grade appendiceal mucinous neoplasm (LAMN): A series of seven cases

The differentiation between a primary mucinous ovarian neoplasm and an extra-ovarian metastasis in the ovary is often challenging in the histopathologic practice. Among various ovarian metastases from the gastro-intestinal tract the low-grade appendiceal mucinous neoplasm (LAMN) is an important differential diagnosis to consider particularly in case of pseudomyxoma peritonei. A newly recognized marker in the routine diagnostic of a mucinous neoplasm in the ovary is SATB2 (Special AT-rich sequence-binding protein 2). The expression of SATB2 is, within cells of epithelial lineages, mainly restricted to the lower gastro-intestinal tract, indicating colorectal or appendiceal cancer origin. We report seven cases of LAMN, which clinically became apparent due to ovarian metastases in context of pseudomyxoma peritonei or at least small foci of peritoneal tumor spread. An immunohistochemical marker-panel including SATB2, CDX2, CK20, CK7, PAX8, ER and PR revealed a strong expression of SATB2 in all seven cases. On the contrary SATB2-negativity could be demonstrated in the 40 cases of mucinous borderline tumors and primary mucinous carcinomas of the ovary. The histopathologic tentative diagnosis of an ovarian metastasis of LAMN could be confirmed in the findings of the Appendix in six of seven cases. This report supports SATB2 as an additional diagnostic marker for the diagnosis of an ovarian manifestation of LAMN.

A qualitative study comparing the assay performance characteristics between the 2007 and the 2013 American Society for Clinical Oncology and College of American Pathologists HER2 scoring methods in mucinous epithelial ovarian cancer

The remarkable success of trastuzumab and other newly developed anti-HER2 (human epidermal growth factor receptor 2) therapies in breast, gastric, or gastroesophageal junction cancer patients has supported us to investigate the HER2 status and its possible therapeutic implication in mucinous epithelial ovarian cancer (EOC). However, there is currently no standardization of HER2 scoring criteria in mucinous EOC. In this study, we aimed to compare both the assay performance characteristics of the 2007 and the 2013 American Society for Clinical Oncology and College of American Pathologists scoring methods. Forty-nine tissue microarray samples of mucinous EOC from Asian women were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests using the 2007 and the 2013 criteria, respectively. The overall concordance between IHC and FISH by the 2007 criteria was 97.92 % (kappa = 0.921), and that by the 2013 criteria was 100% (kappa = 1.000). The percentage of Her2 FISH-amplified cases showed an increasing trend significantly through their corresponding HER2 IHC ordinals by the 2007 and the 2013 criteria, respectively (P < 0.001, P < 0.001). After excluding equivocal cases, the specificity (100%) and positive predictive value (100%) were unchanged under either the 2007 or the 2013 criteria. The sensitivity (100%), negative predictive value (NPV) (100%), and accuracy (100%) of HER2 IHC were higher under the 2013 criteria than those (sensitivity 87.5%, NPV 97.6%, and accuracy 97.9%) under the 2007 criteria. Of the total 49 cases, the number (n = 4) of HER2 IHC equivocal results under the 2013 criteria was 4-fold higher than that (n = 1) under the 2007 criteria (8.16% vs 2.04%). Conclusively, if first tested by IHC, the 2013 criteria caused more equivocal HER2 IHC cases to be referred to Her2 FISH testing than the 2007 criteria. That decreased the false-negative rate of HER2 status and increased the detection rates of HER2 positivity in mucinous EOC.

Assessing the HER2 status in mucinous epithelial ovarian cancer on the basis of the 2013 ASCO/CAP guideline update

Her2 gene amplification and protein overexpression are important factors in predicting clinical sensitivity to anti-HER2 monoclonal antibody therapy in breast, gastric, or gastro-esophageal junction cancer patients. The purpose of this study was to evaluate the HER2 status in the mucinous epithelial ovarian cancer (EOC). Adopting the 2013 American Society for Clinical Oncology and the College of American Pathologists guideline update for HER2 testing, 49 tissue microarray samples of mucinous EOC were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests. The prevalence of HER2 positivity in Asian mucinous EOC was 9 of 49 Asian women (18.37%). The overall concordance was 100% between IHC and FISH results. Her2 gene copies before chromosome-17 correction increased significantly in a stepwise order through the negative, equivocal, and positive IHC result categories (P<0.001), as did the Her2 gene copies after chromosome-17 correction (P<0.001). Of the Taiwanese cohort (n=21), HER2 heterogeneity was 4.76% (1/21) in all but 14.26% (1/7) in HER2-positive cancer. In conclusion, we demonstrated that the prevalence of HER2 positivity in both Asian and white women was comparable; complete HER2 concordance existed between IHC and FISH tests for the Her2 gene copies per tumor cell either before or after correction of chromosome-17, and this can be applied as a potentially valuable tool to analyze the HER2 status. Polysomy-17 was absent under the CEP17 cutoff ≥3. The existence of HER2 heterogeneity can be discerned in certain HER2-expressed primary mucinous EOC in Taiwanese women.