Yasunobu Kanamori

Detection of peritoneal dissemination in gynecological malignancy: evaluation by diffusion-weighted MR imaging

The aim of this study is to evaluate the usefulness of diffusion-weighted (DW) magnetic resonance (MR) imaging in detecting peritoneal dissemination in cases of gynecological malignancy. We retrospectively analyzed MR images obtained from 26 consecutive patients with gynecological malignancy. Peritoneal dissemination was histologically diagnosed in 15 of the 26 patients after surgery. We obtained DW images and half-Fourier single-shot turbo-spin-echo images in the abdomen and pelvis, and then generated fusion images. Coronal maximum-intensity-projection images were reconstructed from the axial source images. Reader interpretations were compared with the laparotomy findings in the surgical records. Receiver-operating characteristic (ROC) curves were used to represent the presence of peritoneal dissemination. In addition, the sensitivity and specificity were calculated. DW imaging depicted the tumors in 14 of 15 patients with peritoneal dissemination as abnormal signal intensity. ROC analysis yielded Az values of 0.974 and 0.932 for the two reviewers. The mean sensitivity and specificity were 90 and 95.5%. DW imaging plays an important role in the diagnosis and therapeutic management of patients with gynecological malignancy.

Glutathione S-transferase-π expression and glutathione concentration in ovarian carcinoma before and after chemotherapy

To clarify the role of glutathione (GSH) in the chemotherapy resistance of ovarian carcinoma, the authors examined the expression of glutathione S‐transferase‐π (GST‐π) and the concentration of glutathione in tumors before and after chemotherapy in the same patients.

PTEN expression is associated with prognosis for patients with advanced endometrial carcinoma undergoing postoperative chemotherapy

The prognostic significance of PTEN expression in endometrial carcinoma has not been clear. We conducted the present study to clarify the relationship between PTEN expression and prognosis in advanced endometrial carcinoma. Of 784 patients with endometrial carcinoma who underwent primary treatment between 1985 and 2000 at 5 institutions, 98 pure endometrioid carcinomas with retroperitoneal lymph node metastasis were provided for our study. PTEN expression was determined by immunohistochemic staining. Negative or mixed PTEN staining was observed in 64 (65.3%) patients. The survival rate for PTEN‐positive patients was significantly higher than that for PTEN‐negative or ‐mixed patients. PTEN‐staining status was not associated with patient age, International Federation of Gynecology and Obstetrics (FIGO) stage, myometrial invasion or histologic grade. Of the 98 patients, 87 received radiation therapy (n = 25) or chemotherapy (n = 62) after surgery. PTEN expression did not relate to survival for patients receiving radiation therapy. In contrast, the survival rate for PTEN‐positive cases was significantly higher than that for PTEN‐negative or ‐mixed cases when patients underwent chemotherapy (62.4% vs. 11.8%). Subsequent multivariate analysis revealed that PTEN staining was an independent prognostic factor for patients undergoing chemotherapy. PTEN‐positive staining was a significant prognostic indicator of favorable survival for patients with advanced endometrial carcinoma who underwent postoperative chemotherapy.

The role of neoadjuvant intraarterial infusion chemotherapy with cisplatin and bleomycin for locally advanced cervical cancer

To clarify the effect of neoadjuvant intraarterial infusion chemotherapy on the cure rate in advanced cervical cancer with bulky tumor, a total of 50 patients were examined prospectively. The clinical stage according to the International Federation of Gynecology and Obstetrics (FIGO) classification included 23 IIb, 6 IIIa, and 21 IIIb. These patients were randomly divided into the neoadjuvant intraarterial infusion chemotherapy group and the control group. There were no significant differences in mean age, FIGO clinical stage, and tumor histology between groups. Twenty-five patients in the former group were given 25 mg/m2 of cisplatin and 15 mg/m2 of bleomycin via each internal iliac artery. If the results of the evaluation indicated that surgery was feasible, radical surgery was performed. The patients whose tumors were inoperable received radiation therapy consisting of external irradiation and intracavitary irradiation. Twenty-five patients in the control group also underwent the same radiation therapy. The overall response rate was 80.0%. Eighteen of 20 responders underwent surgery. The 3-year survival rate was 85.7% for operated patients, 42.9% for patients receiving neoadjuvant intraarterial infusion chemotherapy followed by irradiation, and 49.5% for the control group. In the present study, neoadjuvant intraarterial infusion chemotherapy did not improve the prognosis of patients with advanced cervical cancer compared to radiation therapy alone, and only responders who underwent surgery obtained an advantage in survival.

Sensitivity to anticancer agents and resistance mechanisms in clear cell carcinoma of the ovary.

We conducted the present study to determine the chemoresistance mechanisms in clear cell carcinoma of the ovary (CCC). Five human CCC cell lines (HAC‐2, RMG‐I, RMG‐II, KK, and KOC‐7c) were used in this study. The sensitivity of the cells to the anticancer agents was determined by 3–(4,5–dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and we assessed drug sensitivity by calculating assay area under the curve (AUC) for each agent. The expression of multi‐drug resistance genes (MDR‐1, MRP‐1, MRP‐2) was detected by reverse transcription‐polymerase chain reaction (RT‐PCR). Glutathione (GSH) concentration was measured by an enzymatic assay. Topoisomerase (topo) I activity was assayed in terms of relaxation of supercoiled plasmid substrate DNA. The IC50 to anticancer agents ranged widely. The assay AUC indicated that 3 of 5 cell lines (RMG‐I, RMG‐II, and KK) were sensitive to paclitaxel (PTX), 3 (HAC‐2, RMG‐I, and RMG‐II) were sensitive to 7–ethyl‐10‐hydroxycamptothecin (SN‐38), which is an active metabolite of camptothecin (CPT‐11), and only one (HAC‐2) was sensitive to cisplatin (CDDP). All cell lines were resistant to mitomycin‐C (MMC) and etoposide (VP‐16). The MRP‐1 gene was detected in all cell lines. Only one cell line showed both MRP‐2 and MDR‐1 gene expression. Except for HAC‐2 cells, expression of MRP genes was related to CDDP resistance, and MDR‐1 gene expression was associated with PTX resistance. GSH concentrations increased after exposure to CDDP or MMC in all cell lines. There was a significant correlation between topo‐I enzymatic activity and the response to SN‐38. The present study revealed several resistance mechanisms in CCC and the results suggested that PTX and CPT‐11 might be effective agents to treat CCC.

Mechanisms of Cisplatin Resistance in Clear Cell Carcinoma of the Ovary

Resistance of clear cell carcinoma (CCC) of the ovary to platinum-based chemotherapy is associated with a poor prognosis. However, the mechanism underlying the resistance of CCC to platinum has not yet been understood. We conducted the present study to clarify the mechanism of cisplatin (CDDP) resistance in CCC cells. Eleven CCC and 5 serous adenocarcinoma (SAC) cell lines were used in this study. The IC50 to CDDP ranged from 1.3 to 18.0 µM for CCC cells and from 2.2 to 13.0 µM for SAC cells. There was no correlation between multidrug resistance-associated protein expression and the sensitivity to CDDP in CCC cells. In contrast, the doubling time for CCC cells was significantly longer than that for SAC cells (61.4 vs. 29.8 h). A significant reverse correlation between the S-phase fraction and the response to CDDP was observed (r = 0.647, p < 0.05). The present study suggests that the resistance of CCC to CDDP may be caused by low cell proliferation.

Expression of the c‐myc gene as a predictor of chemotherapy response and a prognostic factor in patients with ovarian cancer

The present study was conducted to determine whether and how expression of the c‐myc gene is related to the response to chemotherapy in patients with epithelial ovarian cancer. This study includes 101 consecutive patients with stage Ic to IV epithelial ovarian cancer who underwent primary surgery followed by platinum‐based chemotherapy. Immunohistochemical studies were performed to detect Ki‐67 and ARF proteins. Apoptotic cells were identified by the terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate biotin nick‐end labeling method. Mutation of the p53 gene was screened by polymerase chain reaction (PCR)‐single strand conformation polymorphism analysis and confirmed by direct sequencing. mRNA expression of c‐myc was determined by means of reverse transcription‐PCR. Apoptotic index (AI) and ARF labeling index (LI) were significantly increased and Ki‐67 LI was decreased after chemotherapy in patients from whom specimens could be obtained before and after chemotherapy. AI, ARF LI, and Ki‐67 LI were not related to p53 gene status. A significant correlation between expression of c‐myc and ARF LI was observed. Of 38 patients with measurable lesion, 23 (60.5%) responded to chemotherapy and 15 (39.5%) did not. Tumors with the wild‐type p53 gene responded significantly better to chemotherapy than did tumors with the mutation. Responders showed a higher expression of c‐myc than nonresponders (468.76 vs. 187.68). The receiver operating characteristic (ROC) curve according to chemoresponse demonstrated that the cut‐off value of c‐myc expression was 200. Patients with c‐myc expression of more than 200 had a better 5‐year survival rate (69.8% vs. 43.5%; 101 patients). Multivariate analysis revealed that c‐myc expression was an independent prognostic factor. Our results suggest that the expression of c‐myc gene is related to chemoresponse and might be a useful prognostic factor in patients with epithelial ovarian cancer.

Expression of hypoxia-inducible factor 1α gene affects the outcome in patients with ovarian cancer

We conducted study to determine whether and how the expression of the hypoxia-inducible factor 1α (HIF-1α) gene relates to outcome in patients with epithelial ovarian cancer. A total of 66 patients with epithelial ovarian cancer, who underwent primary surgery followed by platinum-based chemotherapy, were entered into this study. We confirmed the expression of HIF-1α and the vascular endothelial growth factor (VEGF) by immunohistochemistry. To determine the quantity of HIF-1α and VEGF expression, messenger RNA of each gene was measured by real-time reverse transcription–polymerase chain reaction. The cutoff values were determined by the receiver-operating characteristic curve according to survival. The protein expressions of HIF-1α and VEGF were strongly observed in the cancer cells. The cutoff value of HIF-1α and VEGF gene expression was 6.0 and 3.0, respectively. The expression of HIF-1α did not relate to clinical stage, but tumor with low VEGF expression was observed more frequently in stage I patients. The response rate to chemotherapy did not differ between high and low expression of both genes. The overall survival for patients with high expression of HIF-1α was significantly lower, but disease-free survival did not differ between high and low expression of HIF-1α, whereas both overall and disease-free survival for patients with high expression of VEGF were significantly lower. Multivariate analysis revealed that FIGO stage and HIF-1α expression were independent prognostic factors but that VEGF was not. The present study suggested that the expression level of HIF-1α could be an independent prognostic factor in epithelial ovarian cancer

Cisplatin-resistant HeLa cells are resistant to apoptosis via p53-dependent and -independent pathways.

Since HeLa cells possess very little functional p53 activity, they could be originally resistant to genotoxic stress‐induced apoptosis. Therefore, it is likely that the drug‐resistant cells derived from HeLa cells are more resistant to apoptosis. The aim of this study was to determine whether cisplatin‐resistant cells derived from HeLa cells have an apoptosis‐resistant phenotype. A cisplatin‐resistant cell subline, HeLa/CDDP cells, showed a 19‐fold resistance to cisplatin compared with the parent cells. The subline showed a collateral sensitivity to paclitaxel. An equitoxic dose (IC50) of cisplatin produced DNA fragmentation in HeLa cells but not in HeLa/CDDP cells. Transfection of wild‐type p53gene enhanced the cytotoxicity of cisplatin and cisplatin‐induced apoptosis in HeLa cells but not in HeLa/CDDP cells, although it caused p53 overexpression in both cell lines. The expression of caspase 1 (interleukin‐1β‐converting enzyme, ICE) mRNA and the overexpression of bax protein were observed only in HeLa cells. Paclitaxel‐induced DNA fragmentation appeared less in HeLa/CDDP cells than in HeLa cells. p53gene transfection did not affect the extent of DNA fragmentation in either cell line, suggesting that paclitaxel may induce p53‐independent apoptosis. These findings suggest that HeLa/CDDP cells may have an acquired phenotype that is resistant to p53‐dependent and ‐independent apoptosis.

Genetic diagnosis for chemosensitivity with drug-resistance genes in epithelial ovarian cancer.

We conducted the present study to investigate whether and how chemosensitivity can be determined by means of genetic diagnosis using drug-resistance genes in patients with epithelial ovarian cancer. A total of 75 patients who had epithelial ovarian cancer with measurable lesions were entered into this study. Thirty-three patients received first-line chemotherapy, consisting of paclitaxel and carboplatin (TJ). Forty-two patients received second-line chemotherapy, 22 received EP therapy consisting of etoposide and cisplatin (CDDP), and 20 received irinotecan (CPT-11) and CDDP (CPT-11/CDDP) therapy. Tumor samples were obtained before chemotherapy. MessengerRNA expressions of the multidrug-resistance (MDR)-1 gene, MDR-associated protein-1 (MRP-1), topoisomerase (topo) I, and topo IIα were measured by real-time reverse transcription–polymerase chain reaction. The cutoff values of each gene were determined by the receiver operating characteristic curve. MDR-1 expression was significantly higher in patients who did not respond to TJ therapy. The expression of topo IIα was significantly higher in patients who did respond to EP therapy. The expression of topo I was significantly higher in patients who did respond to CPT-11/CDDP. MRP-1 expression did not differ between responders and nonresponders in all regimens. The cutoff value was 80 for MDR-1, 90 for topo IIα, and 200 for topo I. Next, to evaluate genetic diagnosis, 31 patients were newly added. The accuracy of this genetic diagnosis for chemosensitivity was 85.7% for TJ, 77.8% for EP, and 100.0% for CPT-11/CDDP therapy. The present study suggests that genetic diagnosis may be useful to determine chemosensitivity in patients with epithelial ovarian cancer