ABSTRACT
Purpose@#Circulating tumor DNA (ctDNA) is an attractive source for liquid biopsy to understand molecular phenotypes of a tumor non-invasively, which is also expected to be both a diagnostic and prognostic marker. PIK3CA and KRAS are among the most frequently mutated genes in epithelial ovarian cancer (EOC). In addition, their hotspot mutations have already been identified and are ready for a highly sensitive analysis. Our aim is to clarify the significance of PIK3CA and KRAS mutations in the plasma of EOC patients as tumor-informed ctDNA. @*Methods@#We screened 306 patients with ovarian tumors for somatic PIK3CA or KRAS mutations. A total of 85 EOC patients had somatic PIK3CA and/or KRAS mutations, and the corresponding mutations were subsequently analyzed using a droplet digital polymerase chain reaction in their plasma. @*Results@#The detection rates for ctDNA were 27% in EOC patients. Advanced stage and positive peritoneal cytology were associated with higher frequency of ctDNA detection. Preoperative ctDNA detection was found to be an indicator of outcomes, and multivariate analysis revealed that ctDNA remained an independent risk factor for recurrence (p=0.010). Moreover, we assessed the mutation frequency in matched plasma before surgery and at recurrence from 17 patients, and found six patients had higher mutation rates in cell-free DNA at recurrence compared to that at primary diagnosis. @*Conclusion@#The presence of ctDNA at diagnosis was an indicator for recurrence, which suggests potential tumor spread even when tumors were localized at the time of diagnosis.
ABSTRACT
Objective@#Maternal embryonic leucine zipper kinase (MELK) is receiving an attention as a therapeutic target in various types of cancers. In this study, we aimed to evaluate the prognostic significance of MELK expression in ovarian cancer using clinical samples, and assessed the efficacy of a small molecule MELK inhibitor, OTS167, using patient-derived ovarian cancer cells as well as cell lines. @*Methods@#Expression levels of MELK in 11 ovarian cancer cell lines were confirmed by western blotting. Inhibitory concentration of OTS167 was determined by colorimetric assay.MELK messenger RNA (mRNA) expression was evaluated in 228 ovarian cancer patients by quantitative polymerase chain reaction. Growth inhibition of OTS167 was also evaluated using freshly-isolated primary ovarian cancer cells including spheroid formation condition. @*Results@#MELK mRNA expression was significantly higher in ovarian cancer than in normal ovaries (p<0.001), and high MELK mRNA expression was observed in patients with advanced stage, positive ascites cytology and residual tumor size. Patients with high MELK mRNA expression showed shorter progression-free survival (p=0.001). Expression of MELK was also confirmed in 10 of 11 ovarian cancer cell lines tested, and the half maximal inhibitory concentration of MELK inhibitor, OTS167, ranged from 9.3 to 60 nM. Additionally, OTS167 showed significant growth inhibitory effect against patient-derived ovarian cancer cells, regardless of their tumor locations, histologic subtypes and stages. @*Conclusions@#We demonstrated MELK as both a prognostic marker and a therapeutic target for ovarian cancer using clinical ovarian cancer samples. MELK inhibition by OTS167 may be an effective approach to treat ovarian cancer patients.
ABSTRACT
Objective@#Maternal embryonic leucine zipper kinase (MELK) is receiving an attention as a therapeutic target in various types of cancers. In this study, we aimed to evaluate the prognostic significance of MELK expression in ovarian cancer using clinical samples, and assessed the efficacy of a small molecule MELK inhibitor, OTS167, using patient-derived ovarian cancer cells as well as cell lines. @*Methods@#Expression levels of MELK in 11 ovarian cancer cell lines were confirmed by western blotting. Inhibitory concentration of OTS167 was determined by colorimetric assay.MELK messenger RNA (mRNA) expression was evaluated in 228 ovarian cancer patients by quantitative polymerase chain reaction. Growth inhibition of OTS167 was also evaluated using freshly-isolated primary ovarian cancer cells including spheroid formation condition. @*Results@#MELK mRNA expression was significantly higher in ovarian cancer than in normal ovaries (p<0.001), and high MELK mRNA expression was observed in patients with advanced stage, positive ascites cytology and residual tumor size. Patients with high MELK mRNA expression showed shorter progression-free survival (p=0.001). Expression of MELK was also confirmed in 10 of 11 ovarian cancer cell lines tested, and the half maximal inhibitory concentration of MELK inhibitor, OTS167, ranged from 9.3 to 60 nM. Additionally, OTS167 showed significant growth inhibitory effect against patient-derived ovarian cancer cells, regardless of their tumor locations, histologic subtypes and stages. @*Conclusions@#We demonstrated MELK as both a prognostic marker and a therapeutic target for ovarian cancer using clinical ovarian cancer samples. MELK inhibition by OTS167 may be an effective approach to treat ovarian cancer patients.
ABSTRACT
OBJECTIVE: Although radiation therapy (RT) and concurrent chemoradiotherapy (CCRT) are the global standards for adjuvant therapy treatment in cervical cancer, many Japanese institutions choose chemotherapy (CT) because of the low frequency of irreversible adverse events. In this study, we aimed to clarify the trends of adjuvant therapy for intermediate/high-risk cervical cancer after radical surgery in Japan. METHODS: A questionnaire survey was conducted by the Japanese Gynecologic Oncology Group to 186 authorized institutions active in the treatment of gynecologic cancer. RESULTS: Responses were obtained from 129 facilities. Adjuvant RT/CCRT and intensity-modulated RT were performed in 98 (76%) and 23 (18%) institutions, respectively. On the other hand, CT was chosen as an alternative in 93 institutions (72%). The most common regimen of CT, which was used in 66 institutions (51%), was a combination of cisplatin/carboplatin with paclitaxel. CT was considered an appropriate alternative option to RT/CCRT in patients with risk factors such as bulky tumors, lymph node metastasis, lymphovascular invasion, parametrial invasion, and stromal invasion. The risk of severe adverse events was considered to be lower for CT than for RT/CCRT in 109 institutions (84%). CONCLUSION: This survey revealed a variety of policies regarding adjuvant therapy among institutions. A clinical study to assess the efficacy or non-inferiority of adjuvant CT is warranted.