GIS-Based Analysis for UAV-Supported Field Experiments Reveals Soybean Traits Associated With Rotational Benefit.

Recent advances in unmanned aerial vehicle (UAV) remote sensing and image analysis provide large amounts of plant canopy data, but there is no method to integrate the large imagery datasets with the much smaller manually collected datasets. A simple geographic information system (GIS)-based analysis for a UAV-supported field study (GAUSS) analytical framework was developed to integrate these datasets. It has three steps: developing a model for predicting sample values from UAV imagery, field gridding and trait value prediction, and statistical testing of predicted values. A field cultivation experiment was conducted to examine the effectiveness of the GAUSS framework, using a soybean-wheat crop rotation as the model system Fourteen soybean cultivars and subsequently a single wheat cultivar were grown in the same field. The crop rotation benefits of the soybeans for wheat yield were examined using GAUSS. Combining manually sampled data (n = 143) and pixel-based UAV imagery indices produced a large amount of high-spatial-resolution predicted wheat yields (n = 8,756). Significant differences were detected among soybean cultivars in their effects on wheat yield, and soybean plant traits were associated with the increases. This is the first reported study that links traits of legume plants with rotational benefits to the subsequent crop. Although some limitations and challenges remain, the GAUSS approach can be applied to many types of field-based plant experimentation, and has potential for extensive use in future studies.

Expression of trefoil factor family members correlates with patient prognosis and neoangiogenesis.

PURPOSE: Trefoil factor family (TFF) peptides are thought to contribute to epithelial protection and restitution by virtue of their protease-resistant nature and their strong affinity for mucins. However, they are often overexpressed in tumors, where they seem to be negative prognostic factors, possibly contributing to tumor spread, although the precise mechanisms have not been defined. EXPERIMENTAL DESIGN: Tissue sections from 111 patients with curatively resected advanced gastric carcinoma were immunohistochemically stained for TFF2, ITF (TFF3), and CD34. Microvessel density was expressed as number and area of microvessels. Results were correlated with clinicopathological characteristics and patient survival. RESULTS: Forty-nine (44.1%) and 41 (36.9%) tumors were immunohistochemically positive for TFF3 and TFF2, respectively. Among the various clinicopathologic variables, overexpression of TFF3 had a significant correlation with patient age only. In addition, a significantly higher prevalence of positive TFF2 staining was detected in large, diffuse tumors and in tumors with lymph node metastasis. The number of microvessels had a significant correlation with both TFF3 and TFF2 staining, whereas the area of microvessels had a significant correlation only with TFF3 staining. Both TFF3 and TFF2 were independent predictors of a worse disease-free survival. TFF3 had a gender-specific negative survival advantage, with a 91.3% disease-free survival in female patients with TFF3-negative advanced gastric carcinoma. CONCLUSIONS: Induction of increased tumor vascularity might be one of the mechanisms by which TFFs confer metastatic phenotype and frequent disease recurrence in gastric carcinomas. Female patients with TFF3-negative advanced gastric carcinoma have comparable survival as that reported for patients with early gastric carcinoma.

Metastatic lymph node size and colorectal cancer prognosis.

BACKGROUND: Colorectal cancer patients with lymph node metastasis constitute a heterogeneous population with variable prognoses. In this study, my colleagues and I propose a simpler lymph node (LN) staging system for colorectal cancer. STUDY DESIGN: Four-hundred and twenty-three consecutive colorectal cancer patients were studied. Of these, 36 were excluded because another carcinoma was present. The remaining 387 patients entered the TNM staging analysis. In the survival analysis, 76 patients with distant metastasis were excluded and the remaining 311 patients (LN(-) = 204 and LN(+) = 107) were studied. The diameter of the largest metastatic LN (MLN) was measured on histopathological slides. After examination of various cutpoints and survival outcomes, patients with MLNs were classified into n1 (< or = 9 mm) and n2 (> or = 10 mm) groups, according to size of MLNs (n-stage). RESULTS: Using disease-free survival (DFS) and overall survival (OS) as outcomes, patients were separated into significant prognostic groups by MLN size (univariate, p < 0.0001) (5-year survival, DFS: n0 = 91.5%, n1 = 62.2%, and n2 = 34.4%; OS: n0 = 85.1%, n1 = 63.5%, and n2 = 42.5%) and International Union Against Cancer/American Joint Committee on Cancer (UICC/AJCC) (N-stage) (univariate, p < 0.0001) (5-year survival, DFS: N0 = 91.5%, N1 = 60.5%, and N2 = 36.8%; OS: N0 = 85.1%, N1 = 65.3%, and N2 = 38.0%). But in patients with fewer than 15 LNs examined (n = 31), only the new nodal stage stratified patients into significant groups (OS: p = 0.003 and DFS: p = 0.001). Only the UICC/AJCC N-stage subcategories were further split into significant prognostic groups by MLN size (UICC/AJCC N1: DFS, p = 0.048 and OS, p = 0.11; N2: DFS, p = 0.04 and OS, p = 0.04). n-stage was an independent important factor both in the DFS and OS in multivariable analysis. CONCLUSIONS: MLN size is a strong prognostic variable in colorectal carcinoma. This new metric may help clinicians treating colorectal cancer patients, but additional studies are required before clinical application.

Prognostic impact of hypoxia-inducible factors 1alpha and 2alpha in colorectal cancer patients: correlation with tumor angiogenesis and cyclooxygenase-2 expression.

PURPOSE: Angiogenesis plays an important role in a multitude of biological processes including those of tumorigenesis and cancer progression. Hypoxia is the prime driving factor for tumor angiogenesis and the family of hypoxia-inducible factors (HIFs) plays a pivotal role in this process. The role of HIF in tumor angiogenesis has been underscored in different carcinomas but yet to be reported for colorectal carcinomas. EXPERIMENTAL DESIGN: In this study, we examined HIF [HIF-1alpha (HIF1) and HIF-2alpha (HIF2)] expression in 87 curatively resected colorectal carcinoma samples, and the results were correlated with clinicopathological factors, microvessel density, cyclooxygenase 2 expression, and patient prognosis. RESULTS: HIF1 (44.8%) was more frequently expressed than HIF2 (29.9%). Most of the clinicopathological factors representing the tumor aggressiveness were significantly correlated with overexpression of HIF2 but not with HIF1 expression. HIF2 expression had direct correlation with microvessel density and cyclooxygenase 2 expression. and, in contrast, HIF1 expression had a weak but significant inverse correlation in T1 and T2 tumors only. HIF2 expression alone and the combined expression of HIF1 and HIF2 had significant impact on patient survival. In the multivariate analysis, however, only the combined expression of HIF1 and HIF2 remained independently significant. CONCLUSIONS: Taken together, our results suggest that HIF2 expression may play an important role in angiogenesis and that the combined expression of HIF1 and HIF2 may play an important role in tumor progression and prognosis of colorectal carcinomas. Therefore, HIF expression could be a useful target for therapeutic intervention.

Downregulation of KiSS-1 expression is responsible for tumor invasion and worse prognosis in gastric carcinoma.

KiSS-1 is a promising candidate tumor-suppressor gene and may play a key role in the metastatic cascade. The expression profile and the role of KiSS-1 in cancer progression are largely unknown in most of the cancers, including gastric cancer. In this study, KiSS-1 expression was evaluated by RNase protection assay and localization was done by in situ hybridization in 40 gastric cancers and their adjacent normal gastric mucosa. For comparison with clinicopathologic characteristics and patient prognosis, all patients were divided into 2 groups having high and low KiSS-1 expression by using the median as the cutoff value of KiSS-1 expression as determined by the RNase protection assay. Gastric cancers with low KiSS-1 had frequent venous invasion, distant metastasis and tumor recurrence. Accordingly, patients with low KiSS-1-expressing tumors had a significantly worse overall and disease-free survival. In multivariate analysis, KiSS-1 became the strongest independent prognostic factor among the conventional prognosticators for gastric cancer patients. Collectively, these findings suggest that KiSS-1 may play a crucial role in gastric cancer invasion and could be a useful target for therapeutic intervention.

Transforming growth factor-beta1 induced hepatocyte apoptosis--a possible mechanism for growth of colorectal liver metastasis.

The mechanisms of colonization and growth of metastatic liver tumors from colorectal cancers remain obscure. Forty-three resected colorectal metastatic liver tumors with surrounding livers were evaluated for apoptotic index (AI), proliferation index (PI), and immunohistochemical expressions of TGF-beta1. TGF-beta receptor II, Fas, and Fas-ligand. All the parameters were significantly higher in the peri-tumoral livers than in the tumors with the exception of PI, which was significantly high in tumors. Enhanced TGF-beta1 expression was noticed at the interface between the metastatic tumor and the adjacent liver parenchyma. The AIs of hepatocytes in the TGF-beta1-positive areas (8.7 +/- 7.5%, n = 43) were significantly higher when compared with those in the TGF-beta1-negative areas (2.4 +/- 4.5%, n = 42) (p < 0.001). However, the same kind of correlation could not be found in metastatic tumors. The enhanced expression of TGF-beta1 and hepatocyte apoptosis in the peri-tumoral liver parenchyma may suggest that TGF-beta1 plays a substantial role in the development of colorectal liver metastasis.

Expression of regenerating gene I in gastric adenocarcinomas: correlation with tumor differentiation status and patient survival.

BACKGROUND: Regenerating gene I (REG) was identified as a growth factor for pancreatic islet beta cells. Enhanced REG expression was observed during the healing of gastric mucosa. REG expression was observed in various tumors including gastric carcinoma, but to the authors' knowledge, the correlation between REG expression and clinicopathologic characteristics and patient prognosis have not been evaluated. METHODS: The REG messenger RNA level was analyzed by Northern blot analysis and localization was performed by in situ hybridization and immunohistochemistry in gastric adenocarcinoma specimens. The correlations between REG expression and clinicopathologic features and survival of the patients were analyzed. RESULTS: Of the 68 patients studied, 24 (35%) were positive for REG. There was a significant consistency in the intensity and localization of REG transcript and protein expressions. REG expression was enhanced in advanced T classification tumors and in tumors that were not well differentiated. A significant number of metastatic lymph nodes were present in REG-positive tumors. Overall and disease-free survival were found to be poor for patients with REG-positive tumors. REG expression was reported to be an independent predictor of overall patient survival. CONCLUSIONS: Determination of REG expression may help to identify aggressive gastric tumors and to tailor appropriate therapy for patients with REG-positive tumors.

Expression of cytoplasmic TFF2 is a marker of tumor metastasis and negative prognostic factor in gastric cancer.

Trefoil factor family 2 (TFF2) is a small peptide constitutively expressed in the gastric mucosa, where it plays a protective role in restitution of gastric mucosa. TFF2 has also been shown to be expressed in some gastric cancers, but its role in tumor metastasis and patient prognosis has not been examined. In this study, we examined TFF2 expression at both the mRNA and protein levels and correlated these results with the clinicopathologic characteristics and prognosis of gastric cancer patients. Among the 144 curatively resected samples, 43 (30%) were positive for TFF2. TFF2 expression was preferentially observed in the infiltrating tumor cells sparing the superficial cells. Significantly increased expression of TFF2 was noted in large tumors of the diffuse type. An increased prevalence of TFF2 expression was also found in tumors with advanced T and N stage and in patients with lymphatic and venous invasion. Accordingly, patients with TFF2-expressing tumors had a significantly worse disease-free survival, and in multivariate analysis, this finding remained significant as an independent prognostic factor. Taken together, our results suggest that TFF2 expression may play a role in gastric cancer invasion and as such could be a useful target for therapeutic intervention.

Predictive factors and timing for liver recurrence after curative resection of gastric carcinoma.

BACKGROUND: Advanced and reliable diagnostic methods in order to identify the site of recurrence of gastric cancer in an early stage are needed. METHODS: One hundred twenty patients whose recurrence was confirmed after curative resection for gastric cancer were enrolled in this study. RESULTS: Liver recurrence was evident in 41 patients. Advanced age, tumor invasion into subserosa, intestinal and mixed type of histology, Borrmann type 0 to 2, tumor diameter (<6.5 cm), and tumor marker (carcinoembryonic antigen and alpha-fetoprotein) elevation were related to liver recurrence. By logistic regression analysis, independent risk factors for liver recurrence included Borrmann's classification, histology, and tumor marker elevation. The median time from the primary operation to liver recurrence was shortest in the tumor marker elevation group when compared with other independent predictors. CONCLUSIONS: This information may help to design a better follow-up program and appropriate treatment strategy for gastric cancer patients with liver metastasis.

Prognosis of patients with T2N0 tumors in the alimentary tract: should they be considered as early cancers?

BACKGROUND: T1N0 tumor of the alimentary tract has an excellent long-term prognosis, however, the prognosis of T2N0 tumor has not been uniformly elucidated. MATERIAL AND METHODS: Between February 1981 and April 2000, 75, 424 and 327 patients with node-negative esophageal, gastric and colorectal carcinomas, respectively, underwent curative resection and were included in this study. Long-term prognosis of those node-negative patients stratified by the T-stage were evaluated retrospectively. RESULTS: The 5-year survival rates of patients with T1N0 and T2N0 esophageal tumors were 95.7 and 93.3%, respectively, however those with T3N0 tumor was only 47.6% (p < 0.01). Similarly, the 5-year survival rates of gastric cancer patients with T1-2N0 tumors was 100%, however those with T3N0 and T4N0 tumors were 55.6 and 44.4%, respectively (p < 0.01). The 5-year survival rates of colorectal cancer patients with T1N0 and T2N0 tumors were 97.3 and 97.5%, respectively. In contrast, those with T3N0 and T4N0 tumors were 78.6 and 58.3%, respectively (p < 0.05, T1N0, T2N0 vs. T3N0; p < 0.001, vs. T4N0). CONCLUSION: Patients with T2N0 tumors have an excellent long-term prognosis like T1N0 tumors and both categories could be classified as early cancer in the alimentary tract cancers.

Role of stromal collagen in immunomodulation and prognosis of advanced gastric carcinoma.

Although several hypotheses have been proposed explaining the mechanisms of the immune-privileged status of malignant tumors, the exact pathway is yet to be explored. Tumor stroma plays a vital role in the prognosis of cancer patients; however, the immunomodulatory impact of gastric cancer stroma has not been reported. We have evaluated the amount of stromal collagen and its impact on the infiltration of immune-competent cells into the tumor cell nest in gastric carcinoma. Tissue specimens from 84 advanced gastric carcinoma patients who had undergone a curative resection were evaluated for host immune status (CD8+ T cells), tumor stromal reaction (AZAN staining), tumor Fas ligand expression and incidence of tumor cell apoptosis (by TUNEL). The number of apoptotic tumor cells (apoptotic index [AI]) increased proportionally with an increase in the number of CD8+ T cells within the cancer cell nest (nest CD8) (p = 0.0001). Nest CD8 was inversely correlated with the amount of stromal collagen (p < 0.0001). Nest CD8 and AI became independent predictors of patient survival (p = 0.0023 and p = 0.044, respectively) in Cox's multivariate analysis. The amount of stromal collagen was found to be a significant predictor of disease relapse in univariate analysis (p = 0.0010) but not in multivariate analysis (p = 0.4729). In conclusion, increased nest CD8 produced a survival advantage by inducing tumor cell apoptosis in gastric carcinoma patients. Increased tumor stromal collagen worked as a barrier for CD8+ T-cell infiltration and might be one of the mechanisms of tumor escape from the host immune attack.