Norihiro Masuda

The incremental effect of positron emission tomography on diagnostic accuracy in the initial staging of esophageal carcinoma

The purpose of the current study was to assess whether [18F]fluorodeoxyglucose positron emission tomography (FDG‐PET) provides incremental value (e.g., additional information on lymph node involvement or the presence of distant metastases) compared with computed tomography (CT) in patients with esophageal carcinoma.

Genetic Alterations in Esophageal Cancer

Esophageal cancer is a common malignancy with a striking variation in geographical distribution; a reflection of exposure to specific environmental factors, which are still poorly defined. We discuss the recent progress made in the investigation of the molecular biology of esophageal cancer, addressing the topics of genetic alterations, methylation, overexpression of molecules thought to cause malignant transformation, carcinogenesis, invasion, and metastasis. We review six aspects of the research literature on esophageal cancer: epidemiology and etiology, epidermal growth factor receptor and related growth factor receptors, cell cycle regulatory proteins, transforming growth factor-β/Smad proteins, mismatch repair genes, and other genes. This article provides a conceptual basis for evaluating studies on the molecular mechanism of esophageal carcinogenesis and for devising therapeutic and preventive strategies based on molecular biology. We hope that in the near future, the clinical outcome of patients with esophageal carcinoma will be improved by a better understanding of the basic mechanisms of carcinogenesis.

Usefulness of positron emission tomography for assessing the response of neoadjuvant chemoradiotherapy in patients with esophageal cancer.

BACKGROUND In this study, we retrospectively assessed the performance of 18-F-fluorodeoxyglucose positron emission tomography (FDG-PET) compared with computed tomography (CT) and esophagography for assessing the response of advanced esophageal squamous cell carcinoma (SCC) to neoadjuvant chemoradiotherapy. METHODS We studied 10 patients with thoracic esophageal SCC who received neoadjuvant chemoradiotherapy followed by surgery. Tumor response was assessed by CT, endoscopy, esophagography and FDG-PET before and after neoadjuvant treatment. RESULTS Assessment of the rate of decrease in standardized uptake value (SUV) revealed a partial response (more than 50% decrease) in 5 (50%) of the patients, and assessment of length decrease of FDG uptake showed a partial response in 9 (90%) of the patients. Comparison of the histological response and the rate of decrease of various parameters revealed significant associations between histological response and tumor length (P <0.05), SUV after neoadjuvant therapy (P <0.05), and reduction in the extent of FDG uptake (P <0.01). However histological response was not significantly correlated with the rate of reduction of SUV, for both CT and esophagography. CONCLUSIONS FDG-PET may be of considerable value for predicting the pathologic response of esophageal SCC to neoadjuvant therapy. Despite assessment of SUV before neoadjuvant therapy, low FDG uptake after therapy and reduction in the extent of FDG uptake may provide a reliable assessment of the response to therapy.

Overexpression of p16 and p14ARF is associated with human papillomavirus infection in cervical squamous cell carcinoma and dysplasia.

The CDKN2 gene encodes two structurally different proteins: a cyclin‐dependent kinase inhibitor, p16, which regulates retinoblastoma protein (pRb)‐dependent G1 arrest, and a cell cycle inhibitor, p14ARF, which blocks MDM2‐induced p53 degradation resulting in an increase in p53 levels that leads to cell cycle arrest. Recent studies have revealed that expression of p16 and p14ARF is influenced markedly by the status of pRb and p53, and p16 overexpression has been demonstrated in cervical neoplasia because of functional inactivation of pRb by the human papillomavirus (HPV) E7 protein. To clarify the p14ARF status and the relationship between p16/p14ARF and other cell cycle molecules in cervical carcinogenesis, immunohistochemical analysis of p16, p14ARF, p53 and MDM2 was performed on 65 samples of cervical and genital condylomatous and neoplastic lesions, including nine HPV‐negative tumors. In most cervical cancers and preneoplastic lesions with HPV infection of high and intermediate risk, a marked overexpression of p14ARF as well as the p16 protein (i.e. dotted nuclear immunostaining) was observed. All condyloma acuminata except one and low‐grade dysplasia with HPV infection of low risk, such as HPV 6, immunohistochemically showed completely negative staining for p14ARF, also seen in non‐neoplastic and mesenchymal cells. Our results clearly show that the mode of p14ARF overexpression in cervical neoplastic cells with HPV association differs from that in cancers of other organs without HPV association, and the p14ARF overexpression may be attributable to a negative feedback result in the functional inactivation of the pRb and p53 proteins by HPV oncoproteins.

Increased expression of c-Ski as a co-repressor in transforming growth factor-β signaling correlates with progression of esophageal squamous cell carcinoma

Transforming growth factor‐β (TGF‐β) regulates cell growth inhibition, and inactivation of the TGF‐β signaling pathway contributes to tumor development. In our previous study, altered expression of TGF‐β, TGF‐β‐specific receptors and Smad4 was shown to correlate with tumor progression in esophageal squamous cell carcinoma (SCC). These components, however, were maintained normally in some patients with esophageal SCC. In our study, the mechanism by which aggressive esophageal SCC maintains these components was investigated, with particular emphasis on the participation of c‐Ski and SnoN as transcriptional co‐repressors in TGF‐β signaling. Immunohistochemistry for c‐Ski and SnoN was carried out on surgical specimens obtained from 80 patients with esophageal SCC. The expression of c‐Ski and SnoN was also studied in 6 established cell lines derived from esophageal SCC and compared to an immortalized human esophageal cell line by Western blotting. High levels of expression of c‐Ski, detected immunohistologically, were found to correlate with depth of invasion (p = 0.0080) and pathologic stage (p = 0.0447). There was, however, no significant correlation between expression of SnoN and clinicopathologic characteristics. A significant correlation between c‐Ski and TGF‐β expression was observed. Moreover, in patients with TGF‐β negative expression, the survival rates of patients with c‐Ski positive expression were significantly lower than those of patients with c‐Ski negative expression (p = 0.0486). c‐Ski was expressed at a high level in 5 of 6 cell lines derived from esophageal SCC compared to immortalized esophageal keratinocytes. Furthermore, the cyclin‐dependent kinase (CDK) inhibitor, p21 that was up‐regulated by TGF‐β signaling was expressed at a low level in the 5 cell lines. The expression of c‐Ski protein as a transcriptional co‐repressor in TGF‐β signaling seems to be correlated with tumor progression of esophageal SCC.

Reduced expression of transforming growth factor-β receptors is an unfavorable prognostic factor in human esophageal squamous cell carcinoma

Transforming growth factor‐β (TGF‐β) inhibits epithelial cell proliferation. Inactivation of the TGF‐β signaling pathway is thought to play a role in tumorigenesis. Our purpose was to clarify the correlation between TGF‐β receptors or TGF‐β1 expression and the clinicopathologic characteristics of patients with esophageal squamous cell carcinoma (SCC). Immunohistochemical staining for TGF‐β type I receptor (TGF‐βR‐I), TGF‐βR‐II and TGF‐β1 was performed on surgical specimens obtained from 80 patients with esophageal SCC. Preoperative plasma TGF‐β1 levels were measured and correlated with pathologic features and clinical outcomes. Expression of TGF‐βR‐I and TGF‐βR‐II was reduced in 43 (53.8%) and 23 (28.8%) specimens, respectively. TGF‐β1 was overexpressed in 29 (36.3%). Reduced expression of TGF‐βR‐I and TGF‐βR‐II showed a significant association with depth of invasion (p = 0.0015 and p = 0.0012), lymph node metastasis (p = 0.0309 and p = 0.0059) and pathologic stage (p = 0.0103 and p = 0.0401). Overexpression of TGF‐β1 had a significant association with depth of invasion only (p = 0.0335). Reduced expression of TGF‐βR‐I and TGF‐βR‐II was correlated with cancer‐specific survival (p = 0.0324 and p = 0.0243). The mean preoperative plasma TGF‐β1 level was 10.5 ± 0.8 ng/ml in patients with esophageal carcinoma and was significantly higher compared to healthy controls (p < 0.01). We demonstrate that reduced expression of TGF‐β receptors in esophageal SCC appears to be correlated with depth of invasion, lymph node metastasis, pathologic stage and poor prognosis. TGF‐β receptor expression may play a key role in the progression of this cancer.

Pretreatment evaluation of combined HIF‐1α, p53 and p21 expression is a useful and sensitive indicator of response to radiation and chemotherapy in esophageal cancer

Tumor hypoxia has been known to be associated with resistance to radiation and chemotherapy (CRT). Hypoxia‐inducible factor‐1α (HIF‐1α), a transcription factor induced by hypoxic condition, plays a major role in the pleiotropic response observed under hypoxic conditions. It encodes proteins that play key roles in critical development and physiologic processes, including angiogenesis, glucose transport and erythropoiesis. On the other hand, cell cycle‐ and apoptosis‐control genes p53 and p21 may play major roles in the tumor response to cytotoxic agents such as radiation and chemotherapy. Previous reports have suggested that the regulation of p53 and p21 is HIF‐1‐dependent. Our aim was to evaluate the expression of the HIF‐1α, p53 and p21 proteins by immunohistochemistry in biopsy specimens of esophageal squamous cell carcinoma, which were obtained endoscopically from 65 patients before CRT, and then determine whether the levels of expression of these proteins predicted the clinical effectiveness of CRT in individual cancers. Also, to assess the relationship between expression of these proteins and cell death and cellular proliferation activity, we evaluated Ki67 expression and the apoptosis index (TUNEL). HIF‐1α expression in esophageal cancer was significantly and negatively related to the response to CRT, independently of p53 and p21 expression. Interestingly, 44.4% (12/27) of the HIF‐1α‐negative group showed a complete response to therapy. There was no significant correlation between the expression of HIF‐1α, p53 and p21 and proliferation and apoptosis. HIF‐1α overexpression may predict resistance to CRT and may be a helpful guide in choosing between therapeutic strategies, such as intensive combined modality therapy vs. palliative therapy. Combined immunohistochemical evaluation of HIF‐1α, p53 and p21 protein expression at the pretreatment biopsy is a very useful and powerful indicator of sensitivity to CRT in human esophageal cancer. Our data also indicate the importance of having a clear grasp of the degree of hypoxia (HIF‐1α) of a tumor, rather than its cellular character (proliferation and apoptosis), to indicate the likely impact of CRT.

Significant correlation between expression of heat shock proteins 27, 70 and lymphocyte infiltration in esophageal squamous cell carcinoma

The objective of this study was to clarify the clinicopathologic and prognostic significance of heat shock proteins (HSP) 27 and 70 expression in esophageal squamous cell carcinoma (SCC). Immunohistochemical staining for HSPs 27 and 70 was performed on surgical specimens obtained from 62 patients with esophageal SCC. The expression of both HSPs 27 and 70 correlated inversely with depth of invasion (P<0.05) and pathologic stage (P<0.05), and correlated positively with lymphocyte infiltration (P<0.05). Reduction of HSP 70 expression was significantly correlated with poor prognosis (P<0.05). Patients with HSP 27-negative tumors tended to have a poor prognosis compared with patients with HSP 27-positive tumors. The present findings suggest that HSPs 27 and 70 are significant prognostic factors for esophageal SCC.

Plasma Level of Transforming Growth Factor β1 Measured from the Azygos Vein Predicts Prognosis in Patients with Esophageal Cancer

Purpose: Transforming growth factor (TGF)-β regulates cell growth inhibition. When tumor cells lose their sensitivity to TGF-β growth inhibition, the excess TGF-β that results may act on tumor cells to facilitate tumor development. Previously, we have shown that an elevated systemic TGF-β1 level is not related to tumor progression in esophageal cancer (Y. Fukai et al., Int J Cancer 2003;104:161–6). We considered that systemic inflammation or chronic disease, in addition to the tumor, may influence the plasma TGF-β level. Therefore, we examined the hypothesis that the plasma TGF-β level measured from the azygos vein would independently predict tumor progression and prognosis in patients with esophageal cancer. Experimental Design: Fifty-seven plasma samples were obtained intraoperatively from the azygos vein in patients with esophageal cancer. ELISA was used to quantify the plasma TGF-β1 levels, which were correlated with pathological features and patient survival. Results: The mean plasma TGF-β1 level measured from the azygos vein of esophageal cancer patients was 5.09 ± 0.48 ng/ml (mean ± SE). The survival rates of patients with a high TGF-β1 level (defined as a level above the 4.6 ng/ml level of normal controls) in the azygos vein were significantly lower than those of patients with a low TGF-β1 level (P = 0.0317). Moreover, the TGF-β1 level in the azygos vein was an independent prognostic factor for overall survival (P = 0.0474). Conclusions: The level of plasma TGF-β1 measured from the azygos vein is an independent predictor in patients with esophageal cancer and may reflect tumor progression more specifically because the azygos vein is responsible for venous return from the esophagus.

Predictive value of interleukin-8 and granulocyte elastase in pulmonary complication after esophagectomy

BACKGROUND We investigated whether or not interleukin-8 (IL-8) and granulocyte elastase (GE) can be associated with pulmonary complication after esophagectomy (the most common cause of postoperative death). METHODS We measured serial changes in the IL-8 concentration and GE activity in the plasma and bronchoalveolar lavage fluid (BALF) of 17 patients who had undergone esophagectomy, and examined the relationship between these mediators and postoperative pulmonary complication. RESULTS Pulmonary complication occurred in 6 patients (35%, Pneum+ group). Plasma IL-8 increased at the end of the surgery then decreased, but there was no significant difference between the Pneum+ group and the group without pulmonary complication (11[65%], Pneum- group). IL-8 and GE in BALF were significantly higher in the Pneum+ group than in the Pneum- group on days 1 and 3 after the operation. There was a significant and positive correlation between IL-8 and GE in BALF. CONCLUSIONS Our results indicate that IL-8 and GE in BALF may be useful for the prediction of postoperative pulmonary complication.