Mucinous colorectal adenocarcinoma with signet-ring cells: immunohistochemical and ultrastructural study

A primary mucinous colorectal adenocarcinoma tissue with signet-ring cells, as revealed after histological evaluation, was examined ultrastructurally. The authors also analyzed the immunohistochemical data of the tissue for serotonin, vasoactive intestinal polypeptide (VIP), bombesin, somatostatin, and glucagon, using the peroxidase anti-peroxidase (PAP) method and the immunogold labeling method for light and electron microscope, respectively. Electron microscopically mucinous adenocarcinoma was characterized by the formation of small lumen. Adenocarcinoma cells were full of mucous granules of varying electron density, providing a good environment for the tumor cells to grow. They also exhibited a significant loss of microvilli and intracytoplasmic junctions, which could allow the cells to disseminate. Signet-ring cells were located in the basal site of the ducts or in the lamina propria and appeared neoplastic, with mucin accumulation intracellularly and an eccentric crescent-shaped nucleus. The cytoplasmic organelles were decreased and at the periphery of the cell. The PAP method demonstrated that these cells were strongly positive for bombesin and also positive for vasointestinal polypeptide (VIP). The immunogold method detected bombesin immunoreactivity in the vacuoles as well as in other cytoplasmic membranes, whereas VIP was localized mainly in the plasma membrane. The location of signet-ring cells combined with the immunoreactivity for bombesin and VIP indicated that signet-ring cells were of neuroendocrine origin and probably dedifferentiated enterochromaffin-like endocrine cells. These findings have implications for understanding the biological behavior of these composite malignant tumors and could help in the knowledge of the origin of signet-ring cells.

Two-dimensional electrophoresis and immunohistochemical study of calreticulin in colorectal adenocarcinoma and mirror biopsies

PURPOSE

The purpose of this study was to analyse the polypeptide patterns of colorectal adenocarcinomas and mirror biopsies and to investigate the expression of calreticulin and the relationship of this chaperon to colon cancer.

MATERIALS AND METHODS

The investigation was carried out on 21 adenocarcinomas and 21 mirror biopsies using high-resolution two-dimensional (2D) electrophoresis and immunohistochemical PAP method.

RESULTS

2D electrophoresis revealed several polypeptide patterns that were shown to be upregulated in colorectal adenocarcinomas compared to their mirror biopsies. One polypeptide spot being upregulated in colorectal adenocarcinoma, turned out to be calreticulin. The overexpression of calreticulin was confirmed by further examination in immunohistochemical level.

CONCLUSION

Calreticulin was found overexpressed in colon cancer tissues as compared to the corresponding mirror biopsy tissues. The overexpression was particularly intense to high-malignancy tissues and particularly in the poorly differentiated regions of the tissue. Calreticulin showed a direct relationship to the disease stage, a fact strongly indicating that the functional role of calreticulin is directly associated with tumor growth and metastasis.

Immunoelectron study of pancreatic carcinomas using antibodies to gastrointestinal hormones

The aim of this study was to investigate the ultrastructural appearance of pancreatic adenocarcinoma combined with glucagon and gastrin/cholecystokinin (CCK) expression. The authors investigated the ultrastructure and the immunocytochemistry of 12 human pancreatic cancer specimens and used 3 chronic pancreatitis samples and 6 adjacent histological normal pancreatic tissues (away from the tumor) as controls. The ultrastructural study revealed that chronic pancreatitis tissues were characterized by alterations of the secretory cells. The enzymic and secretory changes were confirmed by electron immunogold results. Glucagon appeared to be located not only in islet alpha cells but also in intermediate alpha acinar cells. The changes were more significant in adenocarcinoma cases. Abnormality in the immunoreaction of the peptides was indicated not only in the tumor area but also in the islets near the cancer. Cells immunoreactive with antibodies were found in all 12 adenocarcinoma cases. Abnormal co-location of both hormones in the same type of endocrine cell was also found. Moderately to poorly differentiated adenocarcinomas were poorly granulated compared with differentiated tumors. Increased and ectopic gastrin/CCK expression was correlated with pancreatic adenocarcinomas exhibiting poor histological grade and neoplastic endocrine cells, providing a potential marker for pancreatic adenocarcinomas with aggressive behavior.

Two-dimensional electrophoretic analysis of cytoplasmic polypeptides expressed by normal and cancerous colon tissues

PURPOSE

To analyse the cytoplasmic polypeptides from malignant and nonmalignant tissues of the large intestine and investigate their relationship to colon cancer.

MATERIALS AND METHODS

The investigation was carried out in 64 large intestinal tissues coming from 32 individuals, using high-resolution 2-dimensional (2D) electrophoresis (2D-PAGE). Thirty specimens were diagnosed as primary adenocarcinomas and 2 were nonmalignant. The other 32 specimens represented mirror biopsies from the respective patient obtained far from the tumor area.

RESULTS

Pathological and nonpathological protein maps from the same patient highlighted several differences associated with malignancy, over and above natural complexity. Polypeptide overexpression was observed in adenocarcinomas, however in poorly differentiated tissues a decline in number and density of protein spots was observed in an area of isoelectric point (PI) between pH 6.3-7.2 and molecular weight (MW) 17.5-24 kDa. Three polypeptides, Pa (51/4.2), Pb (30/6.1) and Pc (21/7.3), were not detected in normal tissues and 27 polypeptides showed significantly increased densities in adenocarcinomas.

CONCLUSION

Pa and Pb polypeptides show significantly increased densities in premature stages of the disease, and Pc provides a promising monitoring tool for the progress of metastases. The low prevalence of the above mentioned polypeptides in tissues from mirror biopsies raises questions as to the extent of the disease far from the tumor area. Also, the quantitative differences are associated with the appearance and development of the disease. We believe that these findings are important, highlighting the complexity and scope for further research in the diagnosis, monitoring and potential therapy of human colon cancer.

Surface topography and ultrastructure correlation between human breast infiltrating ductal carcinoma of non special type and coexisting human breast infiltrating ductal carcinoma of non special type with in situ comedo carcinoma

PURPOSE

To examine the topographical and ultrastructural correlations and differences between breast infiltrating ductal carcinoma (DC) non-special type (NST) and coexisting infiltrating DC NST with in situ comedo, in order to possibly detect differences in their metastatic potential.

MATERIALS AND METHODS

The material examined derived from 22 women with breast cancer. Sixteen breast infiltrating DC NST tissue samples and 6 breast infiltrating DC NST with in situ comedo were studied with primary culture techniques, using transmission and scanning electron microscopy methods.

RESULTS

The surface topography from infiltrating DC NST cells showed microvilli, blebs, ruffles, short and long projections. These features were absent in the normal breast cells. The intensity of these features was dependent on several histological characteristics. Also, the above features in coexisting DC NST with in situ comedo were related to more aggressive cases. The findings concerning the surface topography features have been also found in the ultrastructural level. A very interesting point was that these features consisted partly of cytoplasmic material.

CONCLUSION

We believe that the presence of the features described above might be related to the metastatic potential of breast cancer and in particular to DC NST with in situ comedo.

Immunoelectron study of somatostatin, gastrin and glucagon in human colorectal adenocarcinomas and liver metastases

The aim of this study was to investigate the role and function of somatostatin, glucagon and gastrin in 35 colorectal adenocarcinoma and 25 liver metastases. The investigation was carried out at the electron immunocytochemistry level. Our results showed that well-differentiated tissues have the highest somatostatin levels compared to poorly-differentiated tumors while glucagon levels remain high. We also found gastrin immunoreactivity in cell membranes of poorly-differentiated primary adenocarcinoma tissues and in liver metastases. Low somatostatin expression, high glucagon expression and the presence of gastrin were found in tumors of poor grading and therefore poor prognosis.

Comparative study of serotonin and bombesin in adenocarcinomas and neuroendocrine tumors of the colon

The aim of this study was to investigate serotonin and bombesin expression in colorectal adenocarcinomas and neuroendocrine colorectal tumors to clarify their role in the progression of colon cancer. The investigation was carried out by electron microscope immunocytochemistry. The ultrastructural study revealed that some cases of colorectal adenocarcinomas were characterized by the presence of amphicrine cells containing endocrine granules and mucus granules. Poorly differentiated adenocarcinomas and liver metastases were poorly granulated compared with highly differentiated tumors. Neuroendocrine tumors nevertheless were characterized by the presence of numerous malignant neuroendocrine cells filled with secretory granules and mucus granules. Bombesin appeared to be located in enterochromaffin-like endocrine cells, which are primarily responsible for the production of serotonin. In colorectal adenocarcinomas there was an inverse correlation between serotonin levels and the degree of differentiation. High serotonin levels characterized colorectal adenocarcinomas with composite phenotype and colorectal neuroendocrine tumors. Increased bombesin expression was correlated with colorectal adenocarcinomas exhibiting poor histological grade and their liver metastases. In conclusion, the findings suggest that high serotonin levels may be an indicator of neuroendocrine differentiation, and bombesin may be a useful marker for colorectal adenocarcinomas with aggressive behavior,