Hironobu Shigaki

PIK3CA Mutation Is Associated with a Favorable Prognosis among Patients with Curatively Resected Esophageal Squamous Cell Carcinoma

Purpose: PIK3CA encodes the catalytic subunit of PI3K, p110α. Mutant PIK3CA stimulates the AKT pathway and promotes cancer cell proliferation. PIK3CA mutations have been associated with poor prognosis in patients with colorectal or lung cancer. In contrast, the relationship between PIK3CA mutations and favorable prognoses has been shown in breast cancer. However, the influence of PIK3CA mutations on the prognosis of patients with esophageal squamous cell carcinoma (ESCC) remains unclear. Experimental Design: Using a nonbiased database of 219 curatively resected ESCCs and eight esophageal cancer cell lines, we evaluated PIK3CA mutational status by pyrosequencing. The expression of p53 and phosphorylated AKT (i.e., AKT activation) was evaluated by immunohistochemistry. Results: PIK3CA mutations in exon 9 and/or 20 were detected in 46 cases (21%). No ESCC cell line harbored PIK3CA mutations. PIK3CA mutations were significantly associated with phosphorylated AKT expression, but not with p53 expression, sex, age at surgery, tobacco use, alcohol use, or histologic grade. Compared with wild-type PIK3CA cases, patients with PIK3CA mutations in exons 9 and/or 20 experienced significantly better disease-free survival [log-rank P = 0.0089; univariate HR: 0.37, 95% confidence interval (CI): 0.15–0.75, P = 0.0042; multivariate HR: 0.34, 95% CI: 0.10–0.86, P = 0.021] and overall survival (log-rank P = 0.012; univariate HR: 0.38, 95% CI: 0.16–0.78, P = 0.0060; multivariate HR: 0.35, 95% CI: 0.10–0.90, P = 0.028). Conclusion: PIK3CA mutations in ESCC are associated with longer survival, suggesting its role as a prognostic biomarker. Future studies are needed to confirm this association and to elucidate the exact mechanisms by which PIK3CA mutations affect tumor behavior. Clin Cancer Res; 19(9); 2451–9. ©2013 AACR.

LINE-1 hypomethylation is associated with a poor prognosis among patients with curatively resected esophageal squamous cell carcinoma.

Objective: To investigate the relationship between the long interspersed nucleotide element-1 (L1/LINE-1) methylation level and the disease-free survival and cancer-specific survival in patients with esophageal squamous cell carcinoma (ESCC). Background: Cancer cells exhibit 2 types of deoxyribonucleic acid (DNA) methylation alterations: global DNA hypomethylation and site-specific CpG island promoter hypermethylation. Global DNA hypomethylation plays a role in genomic instability and carcinogenesis. DNA methylation in the LINE-1 repetitive element is a good indicator of the global DNA methylation level. Although the LINE-1 methylation level is attracting interest as a useful marker for predicting cancer prognosis, the prognostic significance of LINE-1 hypomethylaiton in ESCC remains unclear. Methods: Using 217 curatively resected ESCC specimens, we quantified the LINE-1 methylation by utilizing the bisulfite pyrosequencing technology. Promoter methylation levels of MGMT and MLH1 were also evaluated by pyrosequencing. Results: ESCC showed significantly lower LINE-1 methylation levels in comparison with matched normal esophageal mucosa (P < 0.0001; N = 50). LINE-1 hypomethylation was significantly associated with disease-free survival [log-rank P = 0.0008; univariate hazard ratio (HR): 2.32, 95% confidence interval (CI): 1.38–3.84, P = 0.0017; multivariate HR: 1.81, 95% CI: 1.06–3.05, P = 0.031] and cancer-specific survival (log-rank P = 0.0020; univariate HR: 2.21, 95% CI: 1.33–3.60, P = 0.0026; multivariate HR: 1.87, 95% CI: 1.12–3.08, P = 0.018]. MGMT and MLH1 hypermethylation were not associated with patient prognosis. Conclusions: LINE-1 hypomethylation in ESCC is associated with a shorter survival, thus suggesting that it has potential for use as a prognostic biomarker.

Prognostic Impact of Postoperative Complications in 502 Patients With Surgically Resected Esophageal Squamous Cell Carcinoma: A Retrospective Single Institution Study

Objective: To investigate the relationship between postoperative complications and long-term survival in patients with surgically resected esophageal squamous cell carcinoma (ESCC). Summary Background Data: Esophagectomy is the mainstay of curative treatment for ESCC; however, this complex procedure has high risks of postoperative morbidity and mortality. The impact of postoperative complications on long-term survival of such patients remains controversial. Methods: This retrospective single institution study included 502 consecutive patients who had undergone resection of ESCC. The Cox proportional hazard model was used to compute the hazard ratio (HR) for mortality. Results: Postoperative complications (≥Clavien-Dindo classification grade 2) occurred in 217 patients (43%). Overall, postoperative complications did not affect long-term clinical outcomes of these patients. However, patients with pulmonary complications had worse overall survival than those without pulmonary complications [log rank P = 0.0002; univariate HR = 1.51, 95% confidence interval (CI) 1.20–1.88, P = 0.0006; multivariate HR = 1.60, 95% CI 1.05–2.38, P = 0.029]. The effect of pulmonary complications was not significantly modified by clinical or pathological features (P for all assessed interactions >0.05). In addition, postoperative chylothorax was also associated with poor overall survival (log rank P = 0.0021), whereas surgical site infection, recurrent nerve paralysis, cardiovascular complication, and anastomotic leakage were not. Conclusions: Postoperative pulmonary complications may be an independent predictor of poorer long-term survival in patients undergoing resection of ESCCs.

Methylation levels of LINE-1 in primary lesion and matched metastatic lesions of colorectal cancer

Background:LINE-1 methylation level is a surrogate marker of global DNA methylation. LINE-1 methylation in primary colorectal cancers (CRCs) is highly variable and strongly associated with a poor prognosis. However, no study has examined LINE-1 methylation levels of metastatic CRCs in relation to prognosis or assessed the heterogeneity of LINE-1 methylation level within the primary CRCs.Methods:Pyrosequencing was used to quantify LINE-1 methylation level in 42 liver metastases, 26 matched primary tumours, and 6 matched lymph node (LN) metastases. KRAS, BRAF, and PIK3CA mutation status and microsatellite instability (MSI) status were also examined.Results:The distribution of LINE-1 methylation level in liver metastases was as follows: mean, 67.3; range, 37.1–90.1. Primary tumours showed LINE-1 methylation levels similar to those of matched liver and LN metastases. The difference in LINE-1 methylation level between superficial areas and invasive front areas was within 7.0 in all six cases evaluated. Prognostic impact of LINE-1 hypomethylation in liver metastases on overall survival was not observed. The concordance rate was 94% for KRAS, 100% for BRAF, 88% for PIK3CA, and 97% for MSI.Conclusion:Alteration of LINE-1 methylation level may occur in early CRC tumorigenesis, and the LINE-1 methylation level is relatively stable during CRC progression.

LINE-1 Hypomethylation, DNA Copy Number Alterations, and CDK6 Amplification in Esophageal Squamous Cell Carcinoma

Purpose: Global DNA hypomethylation plays a crucial role in genomic instability and carcinogenesis. DNA methylation of the long interspersed nucleotide element-1, L1 (LINE-1) repetitive element is a good indicator of the global DNA methylation level, and is attracting interest as a useful marker for predicting cancer prognosis. Our previous study using more than 200 esophageal squamous cell carcinoma (ESCC) specimens demonstrated the significant relationship between LINE-1 hypomethylation and poor prognosis. However, the mechanism by which LINE-1 hypomethylation affects aggressive tumor behavior has yet to be revealed. Experimental Design: To examine the relationship between LINE-1 hypomethylation and DNA copy number variations, we investigated LINE-1–hypomethylated and LINE-1–hypermethylated ESCC tumors by comparative genomic hybridization array. Results: LINE-1–hypomethylated tumors showed highly frequent genomic gains at various loci containing candidate oncogenes such as CDK6. LINE-1 methylation levels were significantly associated with CDK6 mRNA and CDK6 protein expression levels in ESCC specimens. In our cohort of 129 patients with ESCC, cases with CDK6-positive expression experienced worse clinical outcome compared with those with CDK6-negative expression, supporting the oncogenic role of CDK6 in ESCC. In addition, we found that the prognostic impact of LINE-1 hypomethylation might be attenuated by CDK6 expression. Conclusion: LINE-1 hypomethylation (i.e., global DNA hypomethylation) in ESCC might contribute to the acquisition of aggressive tumor behavior through genomic gains of oncogenes such as CDK6. Clin Cancer Res; 20(5); 1114–24. ©2014 AACR.

Negative lymph-node count is associated with survival in patients with resected esophageal squamous cell carcinoma

BACKGROUND The number of recovered lymph nodes (LNs) is associated with the prognosis of patients with esophageal squamous cell carcinoma (ESCC) undergoing surgical resection. A relationship between negative LN count and patient outcome has been demonstrated in gastrointestinal cancers, including colon and gastric cancers. However, little is known about the prognostic significance of negative LN counts in ESCC. METHODS In this retrospective study we examined patient survival in relation to negative LN count in 252 patients with surgically resected ESCC. Cox proportional hazards models were used to compute hazard ratios (HRs) for death, adjusted for clinical and pathological characteristics. RESULTS Negative LN count was associated with year of operation (P = .0015) and number of fields dissected (P < .0001) but not with tumor location, TNM (ie, tumor, node, metastasis) stage, N status, or histologic grade. Patients with ≥ 31 negative LNs experienced a reduction in overall mortality compared with those with 0-30 negative LNs (log-rank P = .0042; univariate HR = 0.48, 95% confidence interval 0.28-0.79, P = .0035; multivariate HR = 0.41, 95% confidence interval 0.21-0.76, P = .0039). The influence of negative LN count on overall survival was modified by the number of fields dissected (P for interaction = .033); more negative LNs were significantly associated with lower overall mortality in three-field dissection (log rank P < .0001) but not in two-field dissection (log rank P = .93). CONCLUSION A negative LN count was associated with improved survival in patients with curatively resected ESCC.

The role of microRNA in esophageal squamous cell carcinoma

MicroRNAs (miRNA) are 22-nucleotide non-coding RNAs that post-transcriptionally regulate gene expression by base pairing to partially complementary sequences in the 3′-untranslated region of their target messenger RNA. Altered miRNA expression also changes the expression of oncogenes and tumor suppressors, affecting the proliferation, apoptosis, motility and invasibility of gastrointestinal cancer cells, including the cells of esophageal squamous cell carcinoma (ESCC). It has been suggested that various miRNA expression profiles may provide useful biomarkers and therapeutic targets, but to date few studies have been published on the role of miRNA in ESCC. In this review we summarize the identification and characterization of miRNAs involved in ESCC and discuss their potential as biomarkers and therapeutic targets.

Review of chemotherapeutic approaches for operable and inoperable esophageal squamous cell carcinoma

The predominant histological types of esophageal cancer are adenocarcinoma and squamous cell carcinoma. Since these two histological types present as different diseases in terms of their epidemiology, pathologenesis, and tumor biology, separate therapeutic approaches should be developed against each type. While surgical resection remains the dominant therapeutic intervention for patients with operable esophageal squamous cell carcinoma (ESCC), their high rates of tumor recurrence have prompted investigation of multimodality therapies that combine surgery with chemotherapy, radiotherapy, and chemoradiotherapy. In Japan, preoperative chemotherapy with cisplatin (CDDP) plus 5-fluorouracil (5-FU) followed by radical esophagectomy has been accepted as the standard therapeutic approach for resactable clinical Stage II/III ESCC. Similarly, the CDDP and 5-FU regimen has been accepted as the first-line treatment for metastatic and unresectable ESCCs in Japan. Thus, in Japan chemotherapy is an indispensable component of therapy for both resectable and unresectable ESCCs. This review discusses the current knowledge, rationale, and available data regarding chemotherapy for resectable and unresectable ESCCs.

Omental flap after pelvic exenteration for pelvic cancer

Pelvic infection is a significant clinical problem after pelvic exenteration. The clinical benefit of an omental flap in reducing the incidence of such infections is unknown. The aim of this study was to evaluate whether an omental flap after pelvic exenteration reduces the incidence of pelvic infection and the length of postoperative hospital stay. In this study, we demonstrate a safe, effective, simple method for reducing the incidence of pelvic infection using an omental flap. We performed pelvic exenteration for tumors that were suspected to have extensive invasion to the bladder, prostate, or uterus. The omentum was dissected from the transverse colon and greater curvature of the stomach. The flap was based on the right gastroepiploic vessels and tunneled in the retrocolic plane, through the mesentery of the transverse colon and ileocecum, to the defect. Twenty-seven patients were analyzed retrospectively. Ten patients received omental flaps, and 17 patients underwent pelvic exenteration without an omental flap. The incidence of pelvic infection was significantly reduced in the patients with omental flaps.

Abstract 38: The clinical significance of GLUT1 expression in gastrointestinal stromal tumor

Background: Gastrointestinal stromal tumor (GIST) is, though it is as rare as its incidence is about 7 to 20 cases per million population per year, one of the most common non-epithelial malignant tumors of the gastrointestinal tract. Recently it was reported that Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) is useful in diagnosis and evaluation of malignant grade of GIST. At the same time, expression of glucose transporter 1 (GLUT1), which is a membranous protein facilitates the transport of glucose across the plasma membranes into cells, was reported to be correlated with maximum standardized uptake value (SUVmax) in PET/CT and malignant grade of various kinds of cancers. In this study, the correlation of GLUT1 expression with malignant grade in GIST was investigated. Methods: We evaluated the protein expression of GLUT1 in immunohistochemistry in the surgically resected specimens in 67 GIST cases, and analyzed the correlation of the other clinicopathological factors. Results: The number of cases in which the expression of GLUT1 judged to be confirmed in immunohistochemistry was 45 (73.7%). GLUT1 expression group had significantly higher preoperative SUVmax in PET/CT than GLUT1 non-expression group (p = 0.03), had larger tumors in diameter (p = 0.015), and was more malignant by Fletcher classification (p Conclusion: In our study, expression of GLUT1 is correlated with malignant grade in GIST. GLUT1 expression might be a phase of higher metabolic and malignant activity of GIST cells. GLUT1 might be a useful prognostic marker in GIST cases. Citation Format: Daisuke Kuroda, Junji Kurashige, Masaaki Iwatsuki, Tsugio Eto, Yuka Tamaoki, Mayuko Ohuchi, Kenichi Nakamura, Ryuma Tokunaga, Hironobu Shigaki, Hiromitsu Hayashi, Takatsugu Ishimoto, Yoshifumi Baba, Yasuo Sakamoto, Naoya Yoshida, Hideo Baba. The clinical significance of GLUT1 expression in gastrointestinal stromal tumor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 38.