BRCA1/2 reversion mutations in a pan-cancer cohort

Tumor sensitivity to platinum (Pt)-based chemotherapy and poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors is increased by homologous recombination deficiency-causing mutations; in particular, reversion mutations cause drug resistance by restoring protein function. Treatment response is predicted by breast cancer susceptibility gene 1/2 (BRCA1/2) mutations; however, BRCA1/2 reversion mutations have not been comprehensively studied in pan-cancer cohorts. We aimed to characterize BRCA1/2 reversion mutations in a large pan-cancer cohort of Japanese patients by retrospectively analyzing sequencing data for BRCA1/2 pathogenic/likely pathogenic mutations in 3738 patients with 32 cancer types. We identified somatic mutations in tumors or circulating cell-free DNA that could restore the ORF of adverse alleles, including reversion mutations. We identified 12 (0.32%) patients with somatic BRCA1 (n = 3) and BRCA2 (n = 9) reversion mutations in breast (n = 4), ovarian/fallopian tube/peritoneal (n = 4), pancreatic (n = 2), prostate (n = 1), and gallbladder (n = 1) cancers. We identified 21 reversion events-BRCA1 (n = 3), BRCA2 (n = 18)-including eight pure deletions, one single-nucleotide variant, six multinucleotide variants, and six deletion-insertions. Seven (33.3%) reversion deletions showed a microhomology length greater than 1 bp, suggesting microhomology-mediated end-join repair. Disease course data were obtained for all patients with reversion events: four patients acquired mutations after PARP-inhibitor treatment failure, two showed somatic reversion mutations after disease progression, following Pt-based treatment, five showed mutations after both treatments, one patient with pancreatic cancer and BRCA1 reversion mutations had no history of either treatment. Although reversion mutations commonly occur in BRCA-associated cancers, our findings suggest that reversion mutations due to Pt-chemotherapy might be correlated with BRCA1/2-mediated tumorigenesis even in non-BRCA-associated histologies.

Clinical availability and characteristics of multigene panel testing for recurrent/advanced gynecologic cancer

BACKGROUND

Japan's health insurance covers multigene panel testing. This study aimed to determine the potential availability and utility of gene panel testing clinically in gynecologic oncology.

METHODS

We analyzed the characteristics of patients with gynecologic cancer who underwent gene panel testing using FoundationOne® CDx or OncoGuide™ NCC Oncopanel between November 2019 and October 2022.

RESULTS

Out of 102 patients analyzed, 32, 18, 43, 8, and 1 had cervical, endometrial, ovarian cancers, sarcoma, and vaginal cancer, respectively. Druggable gene alteration was found in 70 patients (68.6%; 21 with cervical cancer, 15 with endometrial cancer, 28 with ovarian cancer, 5 with sarcoma, and 1 with other). The most common druggable gene alteration was PIK3CA mutation (n = 21), followed by PTEN mutation (n = 12) and high tumor mutation burden (TMB-H) (n = 11). TMB-H was detected in 5 patients with cervical cancer, 5 with endometrial cancer, and 1 with endometrial stromal sarcoma. Eleven patients (10.8%) received molecularly targeted therapy according to their gene aberrations. Gene panel testing was mostly performed when the second-line treatment was ineffective. Of all 102 patients, 60 did not have recommended treatment, and 15 died or had worsened conditions before obtaining the test results.

CONCLUSION

Through multigene panel testing, although many patients had druggable gene alterations, 10.8% of them received the recommended treatment. TMB-H was mainly observed in cervical/endometrial cancer, suggesting its potential as a therapeutic biomarker of immune checkpoint inhibitors. Furthermore, patients' prognosis and performance status should be considered before performing the test.

Evaluation of the role of intraoperative frozen section and magnetic resonance imaging in endometrial cancer

OBJECTIVE

To evaluate the accuracy of preoperative endometrial biopsy and magnetic resonance imaging (MRI) of endometrial cancer compared with that of intraoperative frozen section.

METHODS

This retrospective study included 264 patients who underwent surgery with intraoperative frozen section for endometrial cancer at our institution between 2014 and 2018. Diagnosis was determined by histologic type, grade, and myometrial invasion. Concordance rate, sensitivity, and specificity of preoperative diagnosis and intraoperative frozen diagnosis were calculated, in comparison to the final pathologic diagnosis.

RESULTS

Preoperative and intraoperative diagnoses showed no statistically significant difference in determining histologic type and grade (P = 0.152). Intraoperative diagnosis showed higher sensitivity for endometrioid carcinoma grade 3 and other types, and higher specificity for grade 1. For myometrial invasion, intraoperative diagnosis showed significantly higher concordance rate than preoperative MRI findings (P < 0.01). Intraoperative diagnosis showed higher sensitivity and specificity in patients with and without myometrial invasion, respectively.

CONCLUSION

Higher agreement between intraoperative and final diagnoses, especially in myometrial invasion, suggests that intraoperative frozen section is a good indicator for appropriate surgical procedure decision making.

Real-world application of next-generation sequencing-based test for surgically resectable colorectal cancer in clinical practice

Aim: To evaluate the significance of next-generation sequencing-based gene panel testing in surgically resectable colorectal cancer by analyzing real-world data. Materials & methods: A total of 107 colorectal cancer patients who underwent curative surgery were included, and correlations between next-generation sequencing data and clinicopathological findings were evaluated. Results: More combination patterns in gene alteration were identified in advanced-stage tumors than in early-stage tumors. The copy number alteration count was significantly lower in right-sided colon tumors and early-stage tumors. Homologous recombination deficiency was more often identified in advanced-stage tumors, and high homologous recombination deficiency status was useful for identifying high-risk stage II tumors. Conclusion: Homologous recombination deficiency was identified as a useful result of gene panel testing with novel utility in clinical practice.

Characteristics and clinicopathological features of patients with ovarian metastasis of endometrial cancer: a retrospective study

There are no criteria for patient selection for ovarian-preserving surgery for endometrial cancer (EC). In this study, intraoperative findings of ovarian swelling (OvS) and the clinicopathological features of patients with EC with or without ovarian metastasis were analysed to identify risk factors for ovarian metastasis. Patients who underwent surgery for EC between 2012 and 2019 at our hospital were enrolled. In univariate analysis, all features were significantly higher in metastasis(+) cases. In multivariate analysis, lymphatic space invasion (LSI), cervical stromal involvement (CSI), peritoneal dissemination, and OvS were significant risk factors. In univariate analysis in stage I and II cases classified without adnexal pathological factors, type 2 histologic type, LSI, CSI, and OvS were significantly higher in metastasis(+) cases. LSI, CSI, and OvS were significant risk factors in multivariate analysis. Patients with type 1 histologic type EC without myometrial invasion ≥1/2, CSI and extrauterine lesions are appropriate for ovarian preservation. IMPACT STATEMENTWhat is already known on this subject? The number of premenopausal patients with endometrial cancer (EC) is increasing. Bilateral oophorectomy for EC results in surgical primary ovarian insufficiency, and thus, surgery with ovarian preservation has been examined. However, there are few reports on risk factors for ovarian metastasis of EC and no established criteria for patient background or pathological factors to determine suitability for ovarian preservation surgery.What do the results of this study add? In univariate analysis, all pathological findings suggestive of disease progression were more frequent in cases with ovarian metastases. In multivariate analysis, lymphatic space invasion (LSI), cervical stromal involvement (CSI), peritoneal dissemination, and ovarian swelling (OvS) were identified as significant risk factors for ovarian metastasis. In an analysis of stage I and II cases classified without adnexal pathological factors, type 2 histologic type, LSI, CSI, and OvS were significantly more common in cases with ovarian metastasis, and LSI, CSI, and OvS emerged as significant risk factors for ovarian metastasis in multivariate analysis.What are the implications of these findings for clinical practice and/or further research? Patients with type 1 histologic type EC without depth of myometrial invasion ≥1/2, CSI, or extrauterine lesions may be appropriate cases for ovarian preservation.

Sentinel node navigation surgery in cervical cancer: a systematic review and metaanalysis

Sentinel node navigation surgery (SNNS) is used in clinical practice for the treatment of cervical cancer. This study aimed to elucidate the appropriate sentinel lymph node (SLN) mapping method and assess the safety and benefits of SNNS. We searched the PubMed, Ichushi, and Cochrane Library databases for randomized controlled trials (RCT) and studies on SLN in cervical cancer from January 2012 to December 2020. Two authors independently assessed study quality and extracted data. We quantitatively analyzed the detection rate, sensitivity/specificity, and complications and reviewed information, including the survival data of SLN biopsy (SLNB) without pelvic lymphadenectomy (PLND). The detection rate of SLN mapping in the unilateral pelvis was median 95.7% and 100% and in the bilateral pelvis was median 80.4% and 90% for technetium-99 m (Tc) with/without blue dye (Tc w/wo BD) and indocyanine green (ICG) alone, respectively. The sensitivity and specificity of each tracer were high; the area under the curve of each tracer was 0.988 (Tc w/wo BD), 0.931 (BD w/wo Tc), 0.966 (ICG), and 0.977 (carbon nanoparticle). Morbidities including lymphedema, neurological symptoms and blood loss were associated with PLND. One RCT and five studies all showed SNNS without systematic PLND does not impair recurrence or survival in early-stage cervical cancer with a tumor size ≤ 2-4 cm. Both Tc w/wo BD and ICG are appropriate SLN tracers. SNNS can reduce the morbidities associated with PLND without affecting disease progression in early-stage cervical cancer.

Discrepancies in pathological diagnosis of endometrial stromal sarcoma: a multi-institutional retrospective study from the Japanese Clinical Oncology Group

Endometrial stromal sarcoma (ESS) is a rare uterine malignancy that requires accurate pathological diagnosis for proper treatment. This study aimed to clarify the discrepancies in the pathological diagnosis of ESS and obtain practical clues to improve diagnostic accuracy. Between 2002 and 2015, 148 patients with low-grade ESS (LGESS), high-grade ESS (HGESS), undifferentiated endometrial sarcoma (UES), or undifferentiated uterine sarcoma (UUS) diagnosed at 31 institutions were included. We performed immunohistochemistry, real-time polymerase chain reaction for JAZF1-SUZ12 and YWHAE-NUTM2A/B, and break-apart fluorescent in situ hybridization for JAZF1, PHF1, and YWHAE. Central pathology review (CPR) was performed by six pathologists. After CPR, LGESS, HGESS, UES/UUS, and other diagnoses were confirmed in 72, 25, 16, and 31 cases, respectively. Diagnostic discrepancies were observed in 19.6% (18/92) of LGESS and 34% (18/53) of HGESS or UUS/UES. Adenosarcomas, endometrial carcinomas, carcinosarcomas, and leiomyosarcomas were common diagnostic pitfalls. JAZF1-SUZ12 transcript, PHF1 split signal, and YWHAE-NUTM2A/B transcript were mutually exclusively detected in 23 LGESS, 3 LGESS, and 1 LGESS plus 3 HGESS, respectively. JAZF1-SUZ12 and YWHAE-NUTM2A/B transcripts were detected only in cases with CPR diagnosis of LGESS or HGESS. The CPR diagnosis of LGESS, HGESS, and UUS was a significant prognosticator, and patients with LGESS depicted a favorable prognosis, while those with UUS showed the worst prognosis. Pathological diagnosis of ESS is often challenging and certain tumors should be carefully considered. The accurate pathological diagnosis with the aid of molecular testing is essential for prognostic prediction and treatment selection.

Clinical Usefulness of Endometrial Cytology in Determining the Therapeutic Effect of Fertility Preserving Therapy

INTRODUCTION

The significance of endometrial cytology in determining the therapeutic efficacy of medroxyprogesterone acetate (MPA) therapy is unclear. This study aimed to evaluate the clinical usefulness of endometrial cytology during MPA therapy.

METHODS

Overall, 77 patients who underwent dilatation and curettage (D&amp;C) to evaluate the therapeutic efficacy of MPA therapy at our hospital between January 2018 and December 2019 were retrospectively analyzed. The results of D&amp;C, cytological evaluation, and other clinicopathological factors were analyzed based on the patients' medical records.

RESULTS

The sensitivity and specificity of cytology were 61% and 92%, respectively, with D&amp;C being the gold standard for diagnosis in 142 D&amp;C/cytological examinations. Among patients with no residual disease on D&amp;C, 5 (4%) had suspicious or positive cytology. Although MPA therapy was terminated in 3 of these patients, only 1 patient had early recurrence, and the frequency of recurrence was similar to that of patients who showed negative results in both D&amp;C and cytology.

DISCUSSION/CONCLUSION

The sensitivity of endometrial cytology in determining the therapeutic effect of MPA therapy is low, and we confirmed that the omission of D&amp;C is unacceptable. Our findings also suggested that the addition of cytological evaluation to D&amp;C during MPA therapy had a low clinical significance.

Lymphadenectomy for primary ovarian cancer: a systematic review and meta-analysis

Objective

To assess the effectiveness of lymphadenectomy at primary debulking surgery (PDS) on the survival of patients with epithelial ovarian cancer (EOC).

Methods

We searched PubMed, Ichushi, and the Cochrane Library. Randomized controlled trials (RCTs) and retrospective cohort studies comparing survival of women with EOC undergoing lymphadenectomy at PDS with that of women without lymphadenectomy were included. We performed a meta-analysis of overall survival (OS), progression-free survival (PFS), and adverse events.

Results

For advanced-stage EOC, 2 RCTs including 1,074 women and 7 cohort studies comprising 3,161 women were evaluated. Meta-analysis revealed that lymphadenectomy was associated with improved OS (hazard ratio [HR]=0.80; 95% confidence interval [CI]=0.70–0.90). However, meta-analysis of 2 RCTs revealed no significant difference in OS between the lymphadenectomy and no-lymphadenectomy groups (OS: HR=1.02; 95% CI=0.85–1.22). For early-stage EOC, 1 RCT comprising 268 women and 4 cohort studies comprising 14,228 women were evaluated. Meta-analysis showed that lymphadenectomy was associated with improved OS (HR=0.75; 95% CI=0.68–0.82). A RCT of early-stage EOC reported that lymphadenectomy was not associated with improved OS (HR=0.85; 95% CI=0.49–1.47). Surgery-related deaths were similar in both groups (risk ratio [RR]=1.00; 95% CI=0.99–1.01); however, blood transfusion was required less frequently in the no-lymphadenectomy group (RR=0.74; 95% CI=0.63–0.86).

Conclusions

Meta-analysis of RCTs and observational studies suggest that lymphadenectomy was associated with improved OS in advanced- and early-stage EOC. However, results from RCTs demonstrate that lymphadenectomy was not associated with improved OS in advanced- and early-stage EOC.

Estimating copy number using next-generation sequencing to determine ERBB2 amplification status

Assessing Erb-b2 receptor tyrosine kinase 2 (ERBB2) amplification status in breast and gastric cancer is necessary for deciding the best therapeutic strategy. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are currently used for assessing protein levels and gene copy number (CN), respectively. The use of next-generation sequencing (NGS) to measure ERBB2 CN in breast cancer is approved by the United States Federal Drug Administration as a companion diagnostic. However, a CN of less than 8 is evaluated as “equivocal”, which means that some ERBB2 amplification cases diagnosed as “HER2 negative” might be false-negative cases. We reviewed the results of gene profiling targeting 160 cancer-related genes in breast (N = 90) and non-breast (N = 19) cancer tissue, and compared the ERBB2 CN results with the IHC/FISH scores. We obtained an estimated CN from the measured CN by factoring in the histological proportion of tumor cells and found that an ERBB2-estimated CN of 3.2 or higher was concordant with the combined IHC/FISH outcome in 98.4% (88/90) of breast cancer cases, while this was not always evident among non-breast cancer cases. Therefore, NGS-estimated ERBB2 CN could be considered a diagnostic test for anti-HER2 therapy after the completion of adequate prospective clinical trials.

Retrospective evaluation of risk-reducing salpingo-oophorectomy for BRCA1/2 pathogenic variant carriers among a cohort study in a single institution

BACKGROUND

Risk-reducing salpingo-oophorectomy is performed for the primary prevention of ovarian cancer in patients with hereditary breast-ovarian cancer syndrome. We performed risk-reducing salpingo-oophorectomy for the first time in Japan in 2008, and we experienced 20 cases of risk-reducing salpingo-oophorectomy through 2019. In the past, the use of risk-reducing salpingo-oophorectomy in Japan was restricted because it was not covered by a Japanese National Health Insurance. Since April 2020, risk-reducing salpingo-oophorectomy has been covered by insurance for patients with breast-ovarian cancer syndrome and pre-existing breast cancer, and this surgery is expected to become more widely implemented in Japan.

METHODS

To contribute to the widespread use of risk-reducing salpingo-oophorectomy in the future, we retrospectively reviewed 20 cases of risk-reducing salpingo-oophorectomy at our hospital cohort study to clarify the issues in its implementation.

RESULTS

The variant genes for which risk-reducing salpingo-oophorectomy was indicated were BRCA1 and BRCA2 in 13 (65%) and 7 patients (35%), respectively. The median age at which risk-reducing salpingo-oophorectomy was performed was 49 years (range, 38-58), 13 patients (65%) had gone through menopause, and 16 patients (80%) had a history of breast cancer. Of the five patients (25%) with vasomotor symptoms, four received Chinese medicine, and only one received hormone replacement therapy. Occult cancer was detected in the removed ovaries in two patients (10%), although no postoperative peritoneal carcinogenesis has been observed to date.

CONCLUSIONS

Women who paid for risk-reducing salpingo-oophorectomy out of pocket were older than the recommended age at which the procedure should be performed, and this may explain the higher rate of occult cancers than previously reported. We need to perform risk-reducing salpingo-oophorectomy at the recommended age to ensure that the procedure is effective for primary prevention.

Atypical vessels in hysteroscopy: Usefulness in prediction of malignant diseases in patients treated with tamoxifen

AIM

Tamoxifen (TAM) is widely used in adjuvant endocrine therapy for invasive breast cancer as a selective estrogen modulator, but this treatment has a risk of developing endometrial malignancy. However, hysteroscopic findings during or after TAM treatment are unclear. The aim of this study is to examine the association between hysteroscopic patterns and malignant histological findings during or after treatment with TAM.

METHODS

The subjects were patients who received TAM after surgery for breast cancer and underwent hysteroscopy at our institution from January 2016 to December 2019. Clinicopathological factors and hysteroscopic findings were collected from medical records and investigated retrospectively. Histologically, atypical endometrial hyperplasia, endometrial cancer, and carcinosarcoma were classified as malignant diseases.

RESULTS

A total of 26 patients were eligible for the study. Hysteroscopic findings included an irregular surface of the endometrium (n = 3, 11.5%), atypical vessels (n = 10, 38.5%), papillary structure (n = 3, 11.5%), and polypoid structure (n = 18, 69.2%). Histological examination revealed malignancy in six patients (23.0%). The percentage of atypical vessels in patients with malignancies was significantly higher than that in patients with a normal endometrium or benign lesion (100% vs. 20%, p = 0.0009). The sensitivity and specificity of atypical vessels in hysteroscopy for diagnosis of malignant diseases were 100% and 80%, respectively.

CONCLUSIONS

Hysteroscopic findings of atypical vessels may be useful for prediction of malignant diseases in patients treated with TAM.

A prospective cohort study on the safety and efficacy of bevacizumab combined with chemotherapy in Japanese patients with relapsed ovarian, fallopian tube or primary peritoneal cancer

OBJECTIVE

this prospective cohort study aimed to assess the safety and efficacy of bevacizumab combined with chemotherapy in Japanese patients with relapsed ovarian, fallopian tube or primary peritoneal cancer.

METHODS

in this study, 40 Japanese patients with relapsed ovarian, fallopian tube or primary peritoneal cancer selected to receive bevacizumab with chemotherapy were enrolled. Patients in poor general condition were excluded. Each patient was monitored prospectively for adverse events, administration status, disease status and survival. Treatment was continued until intolerable adverse events or disease progression. The primary endpoint was safety.

RESULTS

bevacizumab plus platinum-based chemotherapy was performed for 30 patients (median cycle; 16.5), while bevacizumab plus non-platinum chemotherapy was performed for 10 patients (median cycle; 5.5). Among bevacizumab-related adverse events, hypertension occurred in 80% of patients, proteinuria in 83%, mucositis in 25%, bleeding in 20%, thromboembolic events in 5.0% and fistula in 2.5%. Gastrointestinal perforation or other life-threatening lethal adverse events were not observed. Response rate and median progression-free survival were 73% and 19.3 months for patients with bevacizumab plus platinum-based chemotherapy, and 30% and 3.9 months for patients with bevacizumab plus non-platinum chemotherapy, respectively. There was no correlation between response rate and occurrence of adverse events such as hypertension or proteinuria.

CONCLUSION

bevacizumab combined with chemotherapy was tolerable and effective for Japanese patients with relapsed ovarian cancer, fallopian tube cancer or primary peritoneal cancer. Hypertension and proteinuria are frequently occurred and managed properly for continuing treatment.

Evaluating the importance of routine drainage following laparoscopic pelvic lymph node dissection for gynecological malignancies

OBJECTIVE

To determine the efficacy of drainage following pelvic lymph node (PLN) dissection, especially for cases involving laparoscopic surgery.

METHODS

In this retrospective study, 368 patients with malignant gynecological tumors who underwent systemic PLN dissection at Keio University Hospital between January 2012 and October 2018 were enrolled. Drainage tubes were placed in the retroperitoneal fossa in all patients. Medical records were used for data collection.

RESULTS

Laparoscopy was performed on 81 patients, and laparotomy was performed on 287 patients. In the laparoscopy group, tubes were removed 1 day post surgery. In the laparotomy group, tubes were removed 1 day post surgery in 167 patients and 4 days post surgery in 120 patients. Compared with the laparotomy group, we determined the laparoscopy group to have a significantly lower prevalence of lymphocyst (6.2% vs 20.2%, p = 0.002) but a similar prevalence of lymphedema (4.9% vs 5.2%), and symptomatic lymphocyst (2.5% vs 4.5%). The two laparotomy groups did not differ significantly with respect to the prevalence of lymphedema (4.8% vs 5.8%), lymphocyst (20.4% vs 20.0%), or symptomatic lymphocyst (4.2% vs 5.0%).

CONCLUSION

Our results suggest that routine drainage should be omitted, especially in cases involving laparoscopic surgery.

Uterine cervical cancer associated with obstructed hemivagina and ipsilateral renal agenesis (OHVIRA) syndrome: A case report and review of the literature

•Cervical cancer occurring in patients with OHVIRA syndrome is very rare.•This case reports on HPV-negative adenocarcinoma located in the nonvisible cervix.•Colposcopy and imaging are essential for cervical cancer with uterine malformation.•In OHVIRA syndrome, cervical malignancies may be overlooked.

Clinical implications of next-generation sequencing-based panel tests for malignant ovarian tumors

Precision medicine based on cancer genomics is being applied in clinical practice. However, patients do not always derive benefits from genomic testing. Here, we performed targeted amplicon exome sequencing‐based panel tests, including 160 cancer‐related genes (PleSSision‐160), on 88 malignant ovarian tumors (high‐grade serous carcinoma, 27; endometrioid carcinoma, 15; clear cell carcinoma, 30; mucinous carcinoma, 6; undifferentiated carcinoma, 4; and others, 6 (immature teratoma, 1; carcinosarcoma, 3; squamous cell carcinoma, 1; and mixed, 1)), to assess treatment strategies and useful biomarkers for malignant ovarian tumors. Overall, actionable gene variants were found in 90.9%, and druggable gene variants were found in 40.9% of the cases. Actionable BRCA1 and BRCA2 variants were found in 4.5% of each of the cases. ERBB2 amplification was found in 33.3% of mucinous carcinoma cases. Druggable hypermutation/ultramutation (tumor mutation burden ≥ 10 SNVs/Mbp) was found in 7.4% of high‐grade serous carcinoma, 46.7% of endometrioid carcinoma, 10% of clear cell carcinoma, 0% of mucinous carcinoma, 25% of undifferentiated carcinoma, and 33.3% of the other cancer cases. Copy number alterations were significantly higher in high‐grade serous carcinoma (P < .005) than in other histologic subtypes; some clear cell carcinoma showed high copy number alterations that were correlated with advanced stage (P < .05) and worse survival (P < .01). A high count of copy number alteration was associated with worse survival in all malignant ovarian tumors (P < .05). Our study shows that targeted agents can be detected in approximately 40% of malignant ovarian tumors via multigene panel testing, and copy number alteration count can be a useful marker to help assess risks in malignant ovarian tumor patients.

Patient-derived ovarian cancer organoids capture the genomic profiles of primary tumours applicable for drug sensitivity and resistance testing

The use of primary patient-derived organoids for drug sensitivity and resistance testing could play an important role in precision cancer medicine. We developed expandable ovarian cancer organoids in < 3 weeks; these organoids captured the characteristics of histological cancer subtypes and replicated the mutational landscape of the primary tumours. Seven pairs of organoids (3 high-grade serous, 1 clear cell, 3 endometrioid) and original tumours shared 59.5% (36.1–73.1%) of the variants identified. Copy number variations were also similar among organoids and primary tumours. The organoid that harboured the BRCA1 pathogenic variant (p.L63*) showed a higher sensitivity to PARP inhibitor, olaparib, as well as to platinum drugs compared to the other organoids, whereas an organoid derived from clear cell ovarian cancer was resistant to conventional drugs for ovarian cancer, namely platinum drugs, paclitaxel, and olaparib. The overall success rate of primary organoid culture, including those of various histological subtypes, was 80% (28/35). Our data show that patient-derived organoids are suitable physiological ex vivo cancer models that can be used to screen effective personalised ovarian cancer drugs.

Identification of a novel uterine leiomyoma GWAS locus in a Japanese population

Uterine leiomyoma is one of the most common gynaecologic benign tumours, but its genetic basis remains largely unknown. Six previous GWAS identified 33 genetic factors in total. Here, we performed a two-staged GWAS using 13,746 cases and 70,316 controls from the Japanese population, followed by a replication analysis using 3,483 cases and 4,795 controls. The analysis identified 9 significant loci, including a novel locus on 12q23.2 (rs17033114, P = 6.12 × 10^-25 with an OR of 1.177 (1.141-1.213), LINC00485). Subgroup analysis indicated that 5 loci (3q26.2, 5p15.33, 10q24.33, 11p15.5, 13q14.11) exhibited a statistically significant effect among multiple leiomyomas, and 2 loci (3q26.2, 10q24.33) exhibited a significant effect among submucous leiomyomas. Pleiotropic analysis indicated that all 9 loci were associated with at least one proliferative disease, suggesting the role of these loci in the common neoplastic pathway. Furthermore, the risk T allele of rs2251795 (3q26.2) was associated with longer telomere length in both normal and tumour tissues. Our findings elucidated the significance of genetic factors in the pathogenesis of leiomyoma.

SPHK1 Is a Novel Target of Metformin in Ovarian Cancer

The role of phospholipid signaling in ovarian cancer is poorly understood. Sphingosine-1-phosphate (S1P) is a bioactive metabolite of sphingosine that has been associated with tumor progression through enhanced cell proliferation and motility. Similarly, sphingosine kinases (SPHK), which catalyze the formation of S1P and thus regulate the sphingolipid rheostat, have been reported to promote tumor growth in a variety of cancers. The findings reported here show that exogenous S1P or overexpression of SPHK1 increased proliferation, migration, invasion, and stem-like phenotypes in ovarian cancer cell lines. Likewise, overexpression of SPHK1 markedly enhanced tumor growth in a xenograft model of ovarian cancer, which was associated with elevation of key markers of proliferation and stemness. The diabetes drug, metformin, has been shown to have anticancer effects. Here, we found that ovarian cancer patients taking metformin had significantly reduced serum S1P levels, a finding that was recapitulated when ovarian cancer cells were treated with metformin and analyzed by lipidomics. These findings suggested that in cancer the sphingolipid rheostat may be a novel metabolic target of metformin. In support of this, metformin blocked hypoxia-induced SPHK1, which was associated with inhibited nuclear translocation and transcriptional activity of hypoxia-inducible factors (HIF1α and HIF2α). Further, ovarian cancer cells with high SPHK1 were found to be highly sensitive to the cytotoxic effects of metformin, whereas ovarian cancer cells with low SPHK1 were resistant. Together, the findings reported here show that hypoxia-induced SPHK1 expression and downstream S1P signaling promote ovarian cancer progression and that tumors with high expression of SPHK1 or S1P levels might have increased sensitivity to the cytotoxic effects of metformin. IMPLICATIONS: Metformin targets sphingolipid metabolism through inhibiting SPHK1, thereby impeding ovarian cancer cell migration, proliferation, and self-renewal.

Abstract A61: Ascites-derived and tissue-derived ovarian cancer cell primary 3D cultures aimed for personalized medicine

Objective: Ovarian cancer is a poor-prognosis gynecologic disease with over 220,000 diagnoses each year worldwide and a 5-year survival rate less than 40%. In this study, we present a method for isolation and characterization of ovarian cancer cells from patient-derived ascites and tissue samples by using three-dimensional (3D) cell culture.

Materials and Methods: Ascites and tissue samples were obtained from primary ovarian, peritoneal, and fallopian tube cancer patients intraoperatively. Samples were isolated and cultured within 6 hours after collection. After isolation, cells were resuspended in Matrigel and were placed at the center of each well. Optimized medium is added to each well. NanoCulture Plate LH96 (Low-Binding, MH pattern, 96-wells, Medical and Biological Laboratories Co., Ltd., Japan) were used for 3D cell culture. Plates were incubated at 37°C. The cultures were examined for metabolically active cells by ATP assay and medium changed on days 0, 1, 4, 7, 10, and 14.

Results: We successfully obtained ascites-derived primary cell cultures within 1-7 days from 100% (3/31) of the ascites samples and 62% (5/8) from tissue-derived primary cell cultures. Spheroids-like structures were formed in 30% (1/3) of ascites samples and 50% (4/8) of tissue samples. The tumorigenicity and invasiveness of the cells were demonstrated using new 3D spheroid model cultured in vitro by NanoCulture Plate LH96.

Conclusion: Primary ascites and tissue culture of ovarian cancer cells can successfully be cultured by 3D cell culture plates. We may apply this method for drug sensitivity testing; therefore, 3D cell culture has a potential to evaluate the sensitivity of candidate chemotherapeutic drug for individual patients.

Citation Format: Yoshiko Nanki, Akira Hirasawa, Hiroyuki Nomura, Aki Okubo, Manabu Itoh, Tomoko Akahane, Tatsuyuki Chiyoda, Fumio Kataoka, Eiichiro Tominaga, Daisuke Aoki. Ascites-derived and tissue-derived ovarian cancer cell primary 3D cultures aimed for personalized medicine. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A61.

Abstract 5474: Activity of the S1P pathway promotes ovarian cancer and serves as a novel metabolic target of metformin

Sphingosine-1-phosphate (S1P), a metabolite of the phospholipid sphingosine, is a bioactive lipid that directly interacts with specific G-protein-coupled receptors to transduce signals that regulate growth, proliferation and motility. Sphingosine kinases (SPHK1 and 2) catalyze the formation of S1P from sphingosine, thereby regulating S1P homeostasis and the sphingolipid rheostat. Recently, using TCGA data, we noted SPHK1 amplification in several gynecologic cancers and that high expression of SPHK1 was associated with increased mortality in high-grade serous ovarian cancer (HGSOC). The findings reported here show that exposure of HGSOC tumor cells to exogenous S1P, or overexpression of SPHK1, induced migration, proliferation and clonogenecity in multiple ovarian cancer cell lines in vitro. Likewise, in a xenograft mouse model of ovarian cancer, overexpression of SPHK1 markedly enhanced tumor growth. In prior pre-clinical studies, we have demonstrated a strong protective effect of the diabetes medication metformin in ovarian cancer. Interestingly, we found that patients with HGSOC that use metformin for diabetes have reduced serum S1P levels compared to controls, suggesting that the sphingolipid rheostat may be a novel metabolic target of metformin in ovarian cancer. Supporting this, we identified that SPHK1 expression in ovarian cancer cell lines is reduced by treatment with metformin, and further that the reduction of SPHK1 by metformin was mediated through inhibition of transcriptional activity of hypoxia-inducible factors (HIF1α and HIF2α). Finally, we show that overexpression of SPHK1 in HGSOC cell lines enhanced the cytotoxic effects of metformin. Taken together, our data indicates that hypoxia-induced SPHK1 expression and downstream S1P signaling promote tumor progression in HGSOC, and that tumors utilizing this pathway may be particularly vulnerable to the anti-cancer effects of metformin.

Citation Format: Peter C. Hart, Tatsuyuki Chiyoda, Marion Curtis, Xiaojing Liu, Chun-Yi Chiang, Stephanie McGregor, Ricardo Lastra, Jason Locasale, Ernst Lengyel, Iris L. Romero. Activity of the S1P pathway promotes ovarian cancer and serves as a novel metabolic target of metformin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5474.

Loss of BRCA1 in the Cells of Origin of Ovarian Cancer Induces Glycolysis: A Window of Opportunity for Ovarian Cancer Chemoprevention

Mutations in the breast cancer susceptibility gene 1 (BRCA1) are associated with an increased risk of developing epithelial ovarian cancer. However, beyond the role of BRCA1 in DNA repair, little is known about other mechanisms by which BRCA1 impairment promotes carcinogenesis. Given that altered metabolism is now recognized as important in the initiation and progression of cancer, we asked whether the loss of BRCA1 changes metabolism in the cells of origin of ovarian cancer. The findings show that silencing BRCA1 in ovarian surface epithelial and fallopian tube cells increased glycolysis. Furthermore, when these cells were transfected with plasmids carrying deleterious BRCA1 mutations (5382insC or the P1749R), there was an increase in hexokinase-2 (HK2), a key glycolytic enzyme. This effect was mediated by MYC and the STAT3. To target the metabolic phenotype induced by loss of BRCA1, a drug-repurposing approach was used and aspirin was identified as an agent that counteracted the increase in HK2 and the increase in glycolysis induced by BRCA1 impairment. Evidence from this study indicates that the tumor suppressor functions of BRCA1 extend beyond DNA repair to include metabolic endpoints and identifies aspirin as an ovarian cancer chemopreventive agent capable of reversing the metabolic derangements caused by loss of BRCA1. Cancer Prev Res; 10(4); 255-66. ©2017 AACR.

Elevated preoperative neutrophil : lymphocyte ratio as a preoperative indicator of mature cystic teratoma with malignant transformation

AIM

To examine the usefulness of the neutrophil : lymphocyte (N/L) ratio as a cost-effective and simple diagnostic marker of mature cystic teratoma (MCT) with malignant transformation (MT).

METHODS

A retrospective chart review was performed between 1998 and 2013 of 12 MCT patients with MT and between 2009 and 2013 of 130 patients with benign MCT. Data were collected on age, tumor size, white blood cell count with differential counts, tumor marker levels, and presenting features.

RESULTS

Older age, greater tumor size, higher CA19-9 or CA125, higher neutrophil count, and higher N/L ratio were associated with MT on univariate analysis. White blood cell count; lymphocyte count; and the tumor marker squamous cell carcinoma antigen were not associated with MT. Older age (≥median), larger tumor size (≥10 cm), and high N/L ratio (≥5.0) were predictors of MT (hazard ratio, 11.51, 5.87, and 11.11, respectively). Six of 12 patients were diagnosed with MT on preoperative magnetic resonance imaging and five of 12 had an N/L ratio ≥5.0.

CONCLUSIONS

Neutrophil : lymphocyte ratio is a potential preoperative diagnostic marker of MT. The optimal cut-off should be determined in future large-scale studies.

Retrospective Analysis on the Feasibility and Efficacy of Docetaxel-Cisplatin Therapy for Recurrent Endometrial Cancer

AIM

There is poor evidence regarding effective treatment for recurrent endometrial cancer. We treated patients with recurrent endometrial cancer with docetaxel-cisplatin (DP) therapy as second-line or third-line chemotherapy. We aimed to evaluate the feasibility and efficacy of DP therapy for patients with recurrent endometrial cancer.

PATIENT AND METHODS

We included 26 patients diagnosed with recurrent endometrial cancer, who underwent DP chemotherapy at our Institution. Docetaxel at 70 mg/m(2)and cisplatin at 60 mg/m(2)were administered by intravenous injection every 3 weeks. We retrospectively analyzed the clinicopathological factors associated with the response rate (RR) and prognosis. We also analyzed the adverse effects of DP therapy.

RESULTS

Median follow-up was 33.8 months and the median number of therapy cycles was six. Grade 3 or 4 adverse effects included leukopenia (66%), neutropenia (81%), anemia (9%), diarrhea (12%), general fatigue (12%), liver dysfunction (4%), peripheral neuropathy (4%), and hyponatremia (4%). RR was 58% and the median progression-free survival (PFS) was 7.5 months. The group with a treatment-free interval of 6 months or more tended to have better PFS than that with less than 6 months (p=0.01). The group with a platinum-free interval of 6 months or more had significantly better PFS than that with less than 6 months (p=0.09). Although the history of taxane usage was not relevant to prognosis, a taxane-free interval of 12 months or more was associated with a tendency for better PFS (p=0.06).

CONCLUSION

DP therapy was fully feasible and demonstrated efficacy for patients with recurrent endometrial cancer.

Abstract A68: Sphingosine kinase 1 as a mediator and predictor of metformin's protective effect in ovarian cancer

Background: Sphingosine kinase 1 (SPHK1) is over-expressed in multiple cancers including breast and colon cancer. SPHK1 catalyzes the phosphorylation of sphingosine to sphingosine 1-phosphate (S1P). S1P promotes tumorigenesis by inhibiting apoptosis and increasing cell proliferation and angiogenesis. Thus SPHK1 has been evaluated as a therapeutic target in cancer. The antidiabetic drug, metformin, has been reported to have protective effects in several cancers, including ovarian cancer. However, molecular mechanisms mediating the anti-tumor effects of metformin are not fully understood. In this study, we demonstrate that SPHK1 is a novel target of metformin and may predict metformin response in ovarian cancer.

Methods: The S1P signaling cascade was profiled in several ovarian cancer cell lines. Four different ovarian cancer cell lines were treated with 1mM and 5mM metformin and the mRNA and protein levels of SPHK1 were measured by qRT-PCR and western blotting respectively. Next, the Tyk-nu, HeyA8, SNU119, Kuramochi cell lines were stably transfected to overexpression SPHK1 and metformin sensitivity was measured using MTT proliferation assays. Metabolomic analysis was performed on serum from ovarian cancer patients using metformin for diabetes and compared controls (IRB 13248A). Serum samples were analyzed using a Q-Exactive orbitrap mass spectrometer coupled to a Dionex ultimate UHPLC.

Results: In all cell lines tested, metformin suppresses SPHK1 mRNA and protein levels. Analysis of the S1P signaling pathway showed that metformin sensitive cell lines (Tyknu and HeyA8) have high SPHK1 and low S1P lyase (SGPL1) expression, the opposite is true in metformin resistant cell lines (Kuramochi and SNU119). At the same time, S1P receptor 1 (S1PR1) is the main S1P receptor among five S1P receptors (S1PR1-S1PR5) in metformin sensitive cancer cells, however S1PR1 is not dominant in metformin resistant cancer cells. Overexpression of SPHK1 upregulates S1PR1 and increases metformin sensitivity in both metformin sensitive and resistant cell lines. The in vitro findings are augmented by preliminary metabolomic analysis of patient samples that revealed that ovarian cancer patients using metformin for diabetes have lower serum levels of S1P compared to controls.

Conclusions: The findings of this study indicate that SPHK1 is a novel metformin target in ovarian cancer. Specifically, high SPHK1 expression sensitizes cells to metformin and S1P signaling profiles predicts metformin response. Based on these findings we propose that sphingolipid signaling be evaluated as a metformin-response signature in ongoing clinical trials of the drug as adjuvant treatment for ovarian cancer (NCT02122185).

Citation Format: Tatsuyuki Chiyoda, Xiaojing Liu, Ernst Lengyel, Jason Locasale, Iris Romero. Sphingosine kinase 1 as a mediator and predictor of metformin's protective effect in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A68.

LATS1 and LATS2 phosphorylate CDC26 to modulate assembly of the tetratricopeptide repeat subcomplex of APC/C

In budding yeast, the Mitotic Exit Network (MEN) regulates anaphase promoting complex/cyclosome (APC/C) via the Dbf2-Cdc14 signaling cascade. Dbf2 kinase phosphorylates and activates Cdc14 phosphatase, which removes the inhibitory phosphorylation of the APC/C cofactor Cdh1. Although each component of the MEN was highly conserved during evolution, there is presently no evidence supporting direct phosphorylation of CDC14 by large tumor suppressor kinase 1 (LATS1), the human counterpart of Dbf2; hence, it is unclear how LATS1 regulates APC/C. Here, we demonstrate that LATS1 phosphorylates the Thr7 (T7) residue of the APC/C component CDC26 directly. Nocodazole-induced phosphorylation of T7 was reduced by knockdown of LATS1 and LATS2 in HeLa cells, indicating that both of these kinases contribute to the phosphorylation of CDC26 in vivo. The T7 residue of CDC26 is critical for its interaction with APC6, a tetratricopeptide repeat-containing subunit of APC/C, and mutation of this residue to Asp (T7D) reduced the interaction of CDC26 with APC6. Replacement of endogenous CDC26 in HeLa cells with exogenous phosphor-mimic T7D-mutated CDC26 increased the elution size of APC/C subunits in a gel filtration assay, implying a change in the APC/C assembly upon phosphorylation of CDC26. Furthermore, T7D-mutated CDC26 promoted the ubiquitination of polo-like kinase 1, a well-known substrate of APC/C. Overall, these results suggest that LATS1/2 are novel kinases involved in APC/C phosphorylation and indicate a direct regulatory link between LATS1/2 and APC/C.

Effectiveness of third-line chemotherapy in recurrent ovarian cancer patients

OBJECTIVE

Despite recent advances in the treatment of recurrent ovarian cancer, little evidence exists describing the benefit of third- line chemotherapy. The present authors previously reported that the treatment-free interval (TFI) after second-line chemotherapy may predict a survival benefit of third-line chemotherapy, however the length of TFI was uncertain due to limited cases. In this study, the authors evaluated the length of TFI, which is correlated with the effectiveness of third-line chemotherapy and a prognostic factor of third-line chemotherapy.

MATERIALS AND METHODS

The authors reviewed the medical records of 85 women with recurrent ovarian cancer who received third-line chemotherapy after a paclitaxel/carboplatin (PC) regimen as first-line chemotherapy.

RESULTS

The response rate [complete response (CR) + partial response (PR)] and clinical benefit rate [(CBR): CR + PR + stable disease (SD)] during the TFI after second-line chemotherapy for 0-3 months, 3-6 months, and 6-12 months and ≥ 12 months were 9.8%, 0%, 0%, 43.8% and 15.7%, 50%, 66.7%, and 93.8%, respectively. The median overall survival (OS) from the onset of third-line chemotherapy was longer for TFI ≥ 3 months than for TFI 0-3 months (795 days vs. 281 days, p < 0.001). Finally, according to univariate (HR = 0.256; p < 0.001) and multivariate (HR = 0.264; p < 0.001) analyses, TFI was the independent significant prognostic factor for OS.

CONCLUSIONS

TFI less than three months after second-line chemotherapy may predict little survival benefit of third-line chemotherapy.

Simultaneous analysis of the gene expression profiles of cancer and stromal cells in endometrial cancer

To address the role of cancer-stroma interactions, we performed gene expression profiling of both cancer and stroma, using matching samples of endometrial cancer (EC), and analyzed the relationship between the gene expression pattern and prognosis in EC. Sixty EC cases were included in this study (38 nonrecurrent and 22 recurrent). Cancer and stroma were separated by performing laser capture microdissection, and microarray analysis was performed separately on cancer and stromal cells. Genes related with progression-free survival (PFS) in cancer and stroma were analyzed using the Cox regression model, and we established a formula, based on the gene expression pattern of cancer and stroma, to predict recurrence using logistic regression. We estimated the accuracy of the formula using the 0.632 method. All cases were classified based on the 79 selected genes of cancer and stroma related to PFS, based on unsupervised clustering. A total of 143 genes in cancer, and 79 genes in stroma were significantly related with PFS. The estimated area under the curve of receiver operating characteristics curve in cancer and stroma to predict recurrence were 0.800 and 0.758, respectively. Based on the 79 genes of cancer, the 22 recurrent cases were divided into two groups, which generally correlated with the histological grade. In contrast, based on the 79 genes of stroma, the 22 recurrent cases displayed homogeneous gene expression, unrelated to the histological grade. We conclude that gene expression profiles of cancer and stroma can predict the recurrence of EC and stromal that gene expression does not depend on the cancer grade.

Regulation of MKL1 via actin cytoskeleton dynamics drives adipocyte differentiation

Cellular differentiation is regulated through activation and repression of defined transcription factors. A hallmark of differentiation is a pronounced change in cell shape, which is determined by dynamics of the actin cytoskeleton. Here we show that regulation of the transcriptional coactivator MKL1 (megakaryoblastic leukemia 1) by actin cytoskeleton dynamics drives adipocyte differentiation mediated by peroxisome proliferator-activated receptor γ (PPARγ), a master transcriptional regulator of adipogenesis. Induction of adipocyte differentiation results in disruption of actin stress fibres through downregulation of RhoA-ROCK signalling. The consequent rapid increase in monomeric G-actin leads to the interaction of G-actin with MKL1, which prevents nuclear translocation of MKL1 and allows expression of PPARγ followed by adipogenic differentiation. Moreover, we found that MKL1 and PPARγ act in a mutually antagonistic manner in the adipocytic differentiation programme. Our findings thus provide new mechanistic insight into the relation between the dynamics of cell shape and transcriptional regulation during cellular differentiation.

Gene scoring model to predict recurrence in low- and intermediate-risk uterine endometrial cancer: Establishment of uterine print

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Background: Endometrial cancers (ECs) classified as low-, intermediate-, and high-risk, based on clinical and pathological features (CPF: Lurain, 2007) associated with 5%, 15%, and 25% risk of recurrence, respectively. The need for adjuvant chemotherapy in intermediate-risk patients is controversial. We examined whether gene expression profiling can more accurately predict the prognosis of ECs, excluding the CPF-based high-risk group. Methods: Tumor specimens were obtained from 136 ECs including 14 recurrences, excluding high-risk cases. Gene expression profiles were achieved using a custom array consisting of 85 genes associated with EC recurrence and 20 internal controls that were previously screened. We established the gene scoring model (GSM) for recurrence by the logistic regression model in randomly selected 68 ECs including 7 recurrences, and evaluated the accuracy of GSM in other 68 ECs including 7 recurrences. This process was repeated 100 times. We calculated the mean accuracy of GSM and compared it with the accuracy of CPF. We also compared GSM and CPF with respect to progression-free survival (PFS) by use of the log-rank test. Results: Median age of all cases was 58 (29-86) years, and stage, histologic grade, and risk classification based on CPF were as follows: (I, 107; II, 15; III, 14), (G1, 69; G2, 57; G3, 10), and (low, 67; intermediate, 69). The median follow-up period was 1830 (1626-3444) days. The GSM was established based on the expression of 4 genes (PRCC, SPC25, PXDN, and LBXCOR1) and 10 internal controls. The area under the receiver operating characteristic curve of GSM to predict recurrence was 0.87 in 68 test cases. Based on the CPF, 68 cases were classified as 30 low-risk and 38 intermediate-risk, and the sensitivity and specificity of CPF was 86% and 48% each in the 68 test cases. When sensitivity of GSM was fixed at 86%, specificity of 67% was achieved, and 68 cases were classified as 42 risk (-) and 26 risk (+). PFS was significantly related with GSM (p = 0.006); however, it was not related with CPF (p = 0.09). Conclusions: GSM can predict the prognosis of ECs (low- and intermediate-risk) more precisely than CPF.

Abstract 562: The Hippo pathway component LATS1 phosphorylates MYPT1 to counteract PLK1 and regulate G2 DNA damage checkpoint

Background: LATS1 participates in the Hippo pathway, which is best characterized in Drosophila melanogaster. Hippo pathway regulates cell proliferation and cell death to ensure appropriate organ size is maintained. LATS1 knockout mice develop ovarian tumor and soft tissue sarcoma, indicating that LATS1 functions as a tumor suppressor. Indeed, LATS1 expression is reduced in breast cancers due to hypermethylation of its promoter region, which is well correlated with poor prognosis of the patients. However in budding yeast, Dbf2 kinase which is the yeast counterpart of LATS1 phosphorylates and activates Cdc14 phosphatase to faithfully execute mitotic exit. This signaling pathway is known as mitotic exit network (MEN). Since there has been reported no phosphatase substrate of LATS1, we pursued the novel target of LATS1 to elucidate the significance of MEN in mammals and clarified a novel role of LATS1.

Methods: We screened LATS1 substrates using phosphopeptide enrichment techniques coupled with high-accuracy mass spectrometry. We verified that the identified peptides are substrates of LATS1 both in vitro and in vivo. After determining the phosphorylation sites of the novel substrate, we analyzed functional significance of this phosphorylation-mediated signaling pathway.

Results: Phosphoproteomic screening identified myosin phosphatase-targeting subunit1 (MYPT1) as a new substrate for LATS1. LATS1 directly and preferentially phosphorylated serine 445 (S445) of MYPT1. An MYPT1 mutant (S445A) failed to dephosphorylate threonine 210 of polo-like kinase1 (PLK1), thereby activating PLK1. This suggests that LATS1 promotes MYPT1 to antagonize PLK1 activity. Consistent with this, LATS1-depleted HeLa cells or fibroblasts from LATS1 knock-out mice showed increased PLK1 activity. We also found that DNA damage-induced LATS1 activation caused PLK1 suppression via the phosphorylation of MYPT1 S445. Furthermore, LATS1 knock-down caused impairment of G2 checkpoint arrest after DNA damage.

Conclusions: These results indicate that LATS1 phosphorylates a phosphatase as does the yeast Dbf2 and demonstrate a novel link between two mitotic kinases, LATS1 and PLK1. PLK1 is overexpressed in many cancers and its expression levels often correlate with poor prognosis of the patients. The oncogenic properties of PLK1, such as inducing genomic instability by incomplete G2 checkpoint, would be enhanced under the condition of reduced LATS1 expression. Thus, our data raise the intriguing possibility that cancer patients with reduced LATS1 expression in their tumors are potential candidates for treatment with PLK inhibitors. Our data also suggests that mammalian MEN signaling pathway plays an important role for the G2 DNA damage checkpoint response other than mitotic exit.

Citation Format: Tatsuyuki Chiyoda, Shinji Kuninaka, Kenta Masuda, Takatsune Shimizu, Yoshimi Arima, Daisuke Aoki, Hideyuki Saya. The Hippo pathway component LATS1 phosphorylates MYPT1 to counteract PLK1 and regulate G2 DNA damage checkpoint. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 562. doi:10.1158/1538-7445.AM2013-562

LATS1/WARTS phosphorylates MYPT1 to counteract PLK1 and regulate mammalian mitotic progression

In the mitotic exit network of budding yeast, Dbf2 kinase phosphorylates and regulates Cdc14 phosphatase. In contrast, no phosphatase substrates of LATS1/WARTS kinase, the mammalian equivalent of Dbf2, has been reported. To address this discrepancy, we performed phosphoproteomic screening using LATS1 kinase. Screening identified MYPT1 (myosin phosphatase-targeting subunit 1) as a new substrate for LATS1. LATS1 directly and preferentially phosphorylated serine 445 (S445) of MYPT1. An MYPT1 mutant (S445A) failed to dephosphorylate Thr 210 of PLK1 (pololike kinase 1), thereby activating PLK1. This suggests that LATS1 promotes MYPT1 to antagonize PLK1 activity. Consistent with this, LATS1-depleted HeLa cells or fibroblasts from LATS1 knockout mice showed increased PLK1 activity. We also found deoxyribonucleic acid (DNA) damage-induced LATS1 activation caused PLK1 suppression via the phosphorylation of MYPT1 S445. Furthermore, LATS1 knockdown cells showed reduced G2 checkpoint arrest after DNA damage. These results indicate that LATS1 phosphorylates a phosphatase as does the yeast Dbf2 and demonstrate a novel role of LATS1 in controlling PLK1 at the G2 DNA damage checkpoint.

Induction of ZEB proteins by inactivation of RB protein is key determinant of mesenchymal phenotype of breast cancer

We previously showed that depletion of the retinoblastoma protein (RB) induces down-regulation of the adhesion molecule E-cadherin and thereby triggers the epithelial-mesenchymal transition. To further characterize the effect of RB inactivation on the phenotype of cancer cells, we have now examined RB expression in human breast cancer cell lines and clinical specimens. We found that RB-inactive cells exhibit a mesenchymal-like morphology and are highly invasive. We also found that ZEB proteins, transcriptional repressors of the E-cadherin gene, are markedly up-regulated in these cells in a manner sensitive to the miR-200 family of microRNAs. Moreover, depletion of ZEB in RB-inactive cells suppressed cell invasiveness and proliferation and induced epithelial marker expression. These results implicate ZEB in induction of the epithelial-mesenchymal transition, as well as in maintenance of the mesenchymal phenotype in RB-inactive cells. We also developed a screening program for inhibitors of ZEB1 expression and thereby identified several cyclin-dependent kinase inhibitors that blocked both ZEB1 expression and RB phosphorylation. Together, our findings suggest that RB inactivation contributes to tumor progression not only through loss of cell cycle control but also through up-regulation of ZEB expression and induction of an invasive phenotype.

Retrospective study comparing irinotecan and pegylated liposomal doxorubicin in treatment of recurrent platinum-refractory/resistant epithelial ovarian cancer

PURPOSE

The standard regimen for platinum-resistant/refractory recurrent epithelial ovarian cancer (EOC) remains to be determined. In this study, we retrospectively compared the effect of irinotecan (CPT-11) and pegylated liposomal doxorubicin (PLD) in the treatment of platinum-resistant recurrent EOC.

METHODS

Thirty patients who received salvage chemotherapy with CPT-11 or PLD were included in the study. CPT-11 (100 mg/m2) was administered intravenously on days 1, 8 and 15 every four weeks. PLD (50 mg/m2) was administered on day 1 every four weeks. Treatment was repeated, provided that no disease progression or intolerable toxicity occurred.

RESULTS

Response rate in the CPT-11 group and PLD group showed no difference at 26.7% (p = 0.66) in both, while non-PD rate was 73.3% vs. 33.3% (p < 0.05), respectively. Progression-free survival after CPT-11 treatment and PLD treatment was 28.4 weeks and 16.8 weeks (p = 0.07), respectively. Hand-foot syndrome and mucositis were more common in the PLD group than in the CPT-11 group (p < 0.05).

CONCLUSIONS

The results indicate that CPT-11 is a promising drug for the treatment of platinum-resistant recurrent EOC.

EGRI and FOSB gene expressions in cancer stroma are independent prognostic indicators for epithelial ovarian cancer receiving standard therapy

Stromal components interact with cancer cells to promote growth and metastasis. The purpose of this study was to identify genes expressed in stroma, which could provide prognostic information in epithelial ovarian cancer (EOC). Seventy-four patients were included. We performed gene expression profiling and confirmed array data using RT-PCR and immunohistochemistry. By microarray analysis, 52 candidate genes associated with progression free survival (PFS) were identified (P < 0.005). Expression of the early growth response 1 (EGR1) and FBJ murine osteosarcoma viral oncogene homolog B (FOSB) genes was further analyzed. Array data were confirmed by RT-PCR and multivariate analysis demonstrated that both EGR1 and FOSB expression in cancer stroma, and EGR1 expression in cancer are independent prognostic factors in EOC. Immunohistochemically, EGR1 protein is localized in cancer cells and α-smooth muscle actin positive stromal fibroblasts. The EGR1 and FOSB expression in stromal cells and EGR1 expression in cancer cells are prognostic indicators in EOC.

Expression profiles of carcinosarcoma of the uterine corpus-are these similar to carcinoma or sarcoma?

Uterine carcinosarcoma (CS) is usually classified as uterine endometrial carcinoma (EC). However, CS is more aggressive even compared with high grade EC. CS is also reported to undergo epithelial to mesenchymal transition (EMT). In this study, we compared the gene expression profiles of CS, EC, and uterine sarcoma (US) and evaluated the role of EMT and chromosomal aberrations in CS tumor formation. Frozen tissues of 46 patients (14 CS, 24 EC, and 8 US) were included. The similarity was examined by Gene Set Enrichment Analysis (GSEA), Fisher's exact test, and clustering using "intrinsic gene set". We examined the expression of 39 EMT-related genes and evaluated TGF-beta signaling by phospho-SMAD2/3 (p-SMAD2/3) staining. Chromosomal regions differing between CS and EC were identified by chromosomal GSEA and comparative genomic hybridization (CGH) microarrays. Three statistical methods confirmed that CS resembled US rather than EC. Acquired markers of EMT were upregulated and attenuated markers of EMT were downregulated in CS. Immunohistochemistry showed that carcinomatous region of CS have higher expression of p-SMAD2/3 than EC (P = 0.008). Chromosomal GSEA showed that genes located at 19q13 had higher expression in CS. Furthermore, CGH microarray indicated that the TGFB1 locus at 19q13.1 was amplified in 4 of 7 samples. Based on the expression profile, CS resembles US rather than EC. TGF-beta signaling is activated in CS and chromosomal gains at 19q13, which includes the TGFB1 locus, suggest that this may contribute to high expression of TGF-beta and thereby EMT phenotype of CS.

Successfully treated case of epithelioid sarcoma of the vulva

Epithelioid sarcoma of the vulva is an extremely rare and aggressive tumor. This tumor most commonly occurs on the labia majora in women of reproductive age. The molecular pathogenesis remains largely unknown. Only 20 cases of vulvar epithelioid sarcoma have been reported to date and more than half have had poor outcomes. We report a successfully treated case of vulvar epithelioid sarcoma in a 33-year-old woman. We performed a radical vulvectomy with flap reconstruction. Three years after surgery, the patient remains well, showing no evidence of recurrence. Early tissue diagnosis of vulvar epithelioid sarcoma is essential because this tumor can be clinically misdiagnosed as a benign lesion. Gynecologists should be aware of this rare tumor variant and carefully plan the treatment.

Establishment of a choriocarcinoma model from immortalized normal extravillous trophoblast cells transduced with HRASV12

Gestational choriocarcinoma is a malignant trophoblastic tumor. The development of novel molecular-targeted therapies is needed to reduce the toxicity of current multiagent chemotherapy and to treat successfully the chemoresistant cases. The molecular mechanisms underlying choriocarcinoma tumorigenesis remain uncharacterized, however, and appropriate choriocarcinoma animal models have not yet been developed. In this study, we established a choriocarcinoma model by inoculating mice with induced-choriocarcinoma cell-1 (iC³-1) cells, generated from HTR8/SVneo human trophoblastic cells retrovirally transduced with activated H-RAS (HRASV12). The iC³-1 cells exhibited constitutive activation of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways and developed into lethal tumors in all inoculated mice. Histopathological analysis revealed that the tumors consisted of two distinct types of cells, reminiscent of syncytiotrophoblasts and cytotrophoblasts, as seen in the human choriocarcinoma. The tumors expressed HLA-G and cytokeratin (trophoblast markers) and hCG (a choriocarcinoma marker). Comparative analysis of gene expression profiles between iC³-1 cells and parental HTR8/SVneo cells revealed that iC³-1 cells expressed matrix metalloproteinases, epithelial-mesenchymal transition-related genes, and SOX3 at higher levels than parental trophoblastic cells. Administration of SOX3-specific short-hairpin RNA decreased SOX3 expression and attenuated the tumorigenic activity of iC³-1 cells, suggesting that SOX3 overexpression might be critically involved in the pathogenesis of choriocarcinoma. Our murine model represents a potent new tool for studying the pathogenesis and treatment of choriocarcinoma.

The cell cycle regulator Cdh1 controls the pool sizes of hematopoietic stem cells and mature lineage progenitors by protecting from genotoxic stress

Various key cell cycle components, especially G0/G1 regulators, have effects not only on cell proliferation but also on cell differentiation. Cdh1, one of the co-activators that maintain anaphase-promoting complex/cyclosome activity, plays a crucial role in the mitotic phase, but has recently been identified as a G0/G1 regulator, suggesting that the role of Cdh1 in cell differentiation. Here, we generated Cdh1 conditional gene-trap mice to examine Cdh1 functions in adult tissues by overcoming the embryonic lethality of Cdh1 homozygous gene-trap mice. We focused on the hematopoietic system and found that Cdh1-deficient mice exhibited a general decrease in mature lineage progenitor cells and a significant increase in short-term hematopoietic stem cells. This phenomenon became conspicuous by irradiation shortly after Cdh1 downregulation, suggesting that Cdh1 regulates the pool sizes of the hematopoietic stem cells and mature lineage progenitor cells by protecting cells from genotoxic stress. We also found that the irradiation-induced G2/M checkpoint was defective in Cdh1-deficient BM cells, causing the loss of stem/progenitor cells. This is the first report revealing Cdh1 function in adult hematopoiesis and showing a role of Cdh1 in a G2/M checkpoint regulation in vivo.

The chemosensitivity of nodal metastases in recurrent epithelial ovarian cancer

PURPOSE

In this study, we compared second-line chemotherapy effects of nodal metastases with other metastases sites.

METHODS

The medical records of 44 women with recurrent ovarian cancer who received second-line chemotherapy were retrospectively reviewed.

RESULTS

Median age at the time of second-line chemotherapy was 55 years (range: 31-74). Recurrent sites were as follows: 29 patients had a solitary site (abdominal cavity: 8; lymph node: 3; pelvic cavity: 10; liver: 4; lung: 4) and 15 patients had multiple sites In total, the response rate was 30% (CR: 8, PR: 5). The response rate in sensitive cases was higher than in refractory/resistant cases (50% vs 5% p = 0.002). However, age, chemotherapy regimen, histologic type and number of diseases were not related with chemotherapy effect. In all diseases, response rate tended to be higher in lymph node disease than in the others (44% vs 27%). In both sensitive and refractory/resistant cases, response rate tended to be higher in lymph node disease.

CONCLUSION

The response rate for lymph node diseases tended to be relatively high. Further study analyzing survival will be required to conclude the chemotherapy effect.

Expression of hypoxia-inducible 2 (HIG2) protein in uterine cancer

For both cervical cancer (UCC) and endometrial cancer (EMC) there are no effective prognostic markers. In this study, we evaluated HIG2 protein expression in 332 uterine cancers (186 UCCs and 146 EMCs) and examined the relationship between HIG2 protein expression and clinical factors, including prognosis. Totally, HIG2 expression was detected in 58% of UCC and 66% of EMC. However, there was no significant relationship between HIG2 expression and age, clinical stage and histology in either UCC or EMC. In addition, HIG2 protein expression was not related to prognosis of UCC or EMC. The positivity rate of HIG2 protein was 56% and 61% in early-stage UCC and EMC, respectively and 67% in non-squamous cell carcinoma of UCC. The positivity rate of HIG2 protein was high even in early-stage UCC and EMC

Effects of third-line chemotherapy for women with recurrent ovarian cancer who received platinum/taxane regimens as first-line chemotherapy

PURPOSE

At present, it remains unclear whether the third-line chemotherapy has clinical benefit. In this study, we retrospectively evaluated the effect of third-line chemotherapy.

METHODS

We reviewed the medical records of 40 women with recurrent epithelial ovarian cancer (EOC) who received third-line chemotherapy after platinum/taxan regimens as first line chemotherapy.

RESULTS

In the first recurrence, 23 cases were platinum-sensitive and 17 cases were platinum-resistant. The cases for which the treatment-free interval from second-line chemotherapy (TFI) was a 3 months had a higher non-PD rate than those with TFI < 3 months (86% vs 33%, p = 0.002). In addition, the median overall survival (OS) was longer for TFI > or = 3 months than for TFI < 3 months (1195 days vs 235 days, p = 0.004). Finally, TFI was an independent significant prognostic factor by univariate (HR 3.28, p = 0.006) and multivariate (HR 3.21, p = 0.018) proportional hazard tests.

CONCLUSION

TFI from second-line chemotherapy may predict a survival benefit of third-line chemotherapy.

Use of amplification of the 8q24 and 20q11–13 loci to predict progression-free survival of advanced epithelial ovarian cancer patients receiving standard therapy

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Background: The purpose of this study was to identify genes that predict the progression free survival (PFS) of advanced epithelial ovarian cancer (aEOC) receiving standard therapy. Methods: We performed expression analysis using GeneChip (Human Genome U133 plus 2.0 Array) in aEOC cells produced by laser-based microdissection. Thirty three aEOC patients (stage IIc: 4, III: 19, IV: 10; serous adenocarcinoma: 21, endometrioid adenocarcinoma: 5, undifferentiated: 7) were included in this array study. All cases received staging laparotomy, cytoreductive surgery, and adjuvant chemotherapy (carboplatin + paclitaxel) as primary therapy. Results: Class comparison analysis between groups of NED (no evidence of disease) and non-NED identified 46 genes that exhibited significant differences (p < 0.001). Among them, 6 (13%) genes are located in 8q24 and 9 (19.6%) genes are located in 20q11–13. Finally, we focused on 8q24 and 20q11–13 loci, and confirmed array data using real-time quantitative PCR in 94 validation sets. The validation showed that ZNF7, MAF1, ADRM1, and GNAS amplification was related with PFS (p < 0.05, respectively). Conclusions: The amplification of 8q24 and 20q11–13 can predict the PFS of aEOC and these genes may be new biomarkers for aEOC.

No significant financial relationships to disclose.