PLK (polo-like kinase), the human counterpart of polo in Drosophila melanogaster and of CDC5 in Saccharomyces cerevisiae, belongs to a family of serine/threonine kinases. It is intimately involved in spindle formation and chromosome segregation during mitosis. The purpose of this study was to determine whether PLK1 is overexpressed in primary colorectal cancer specimens as compared with normal colon mucosa and to assess its relation to other kinases as a potential new tumor marker. In the present study, immunohistochemical analyses were performed of PLK1 expression in 78 primary colorectal cancers as well as 15 normal colorectal specimens. Furthermore, we examined the relationship between other kinases, Aurora-A and Aurora-C, and PLK1 expression. In normal colon mucosa, some crypt cells showed weakly positive staining for PLK1 in 13 out of 15 cases, the remaining cases being negative. Elevated expression of PLK1 was observed in 57 (73.1%) of the colorectal cancers, statistically significant associations being evident with pT (primary tumor invasion) (P = = = =0.0006, Mann-Whitney U test), pN (regional lymph nodes) (P = = = =0.008, χ χ χ χ 2 test) and the Dukes' classification (P = = = =0.0005, MannWhitney U test). Mean proliferating cell nuclear antigen-labeling index was 52.3%, with a range of 24.1% to 77.3%. Values for lesions with high and low PLK1 expression were 54.7 ± ± ± ±10.3% (mean ± ± ± ±SD) and 45.9 ± ± ± ±11.9% (P = = = =0.002, Student's t test). PLK1 was significantly associated with Aurora-A, but PLK1 staining was more diffuse and extensive than for Aurora-A or Aurora-C. Interestingly, PLK1 overexpression was significantly associated with p53 accumulation in colorectal cancers. Our results suggest overexpression of PLK1 might be of pathogenic, prognostic and proliferative importance, so that this kinase might have potential as a new tumor marker for colorectal cancers. (Cancer Sci 2003; 94: 148-152)
These findings indicate that TNP-470 and lentinan could prove useful for preventing the development of metachronous liver metastases from colorectal cancers after curative resection.
Even though angiogenesis inhibitor is thought to be one of the promising agents in tumor dormancy therapy, its optimal administration is still unknown. Therefore, the efficient protocol using TNP-470 was examined regarding its treatment affect against spontaneous liver metastases of colon tumors in the rabbit. A spontaneous liver metastases model was established in the rabbit by the inoculation of VX-2 tumors into the subserosal space of the colon. The therapeutic effect of TNP-470 was then investigated by monitoring both the number of metastatic nodules in the liver and the microvessel density (MVD) in the tumor by immunohistochemical staining using anti-CD31 monoclonal antibody. TNP-470 did not show any effect on the primary tumor. It was able to reduce the metastatic spread to liver when it was administered at the microscopic metastatic stage. Treatment at this stage, however, was not able to sufficiently control the disease. These results indicated that TNP-470 could efficiently cause the tumor to enter into a dormant state by inhibiting angiogenesis when it was used at the initial stage of the metastatic process in the liver. Regarding its clinical application, TNP-470 might be useful for preventing the metachronous liver metastases of colorectal cancer when it is administered as adjuvant therapy after curative surgery.
Background
Invasion is more likely to occur in gastric cancer affecting larger areas. Poorly differentiated adenocarcinoma tends to invade deep. The cardiac region prefers submucosal invasion because the submucosa is coarser than the other regions.
Case presentation
A 75-year-old man presented with a chief complaint of abdominal discomfort and weight loss. Esophagogastroduodenoscopy revealed an irregular ulcerative lesion with partial redness of the upper body and lesser curve of the stomach. A continuous shallow depressed lesion invaded the abdominal esophagus by approximately 40 mm. Poorly differentiated adenocarcinomas (por, sig) were observed on biopsy. Grossly, the cancer appeared to extend into the muscle layer; however, we could not confirm invasion into the muscle layer in our biopsy tissue. We diagnosed the lesion as a superficial spreading type of advanced gastric cancer and performed a total gastrectomy, D2-lymph node dissection (spleen preservation), Roux-en-Y reconstruction, and cholecystectomy. Postoperative histopathological examination revealed extensive infiltration of poorly differentiated adenocarcinoma (90 mm × 55 mm), and all were intramucosal lesions. The final pathological diagnosis was T1a, N0, M0, and Stage IA. The postoperative course was uneventful and the patient was discharged on postoperative day (POD) 11. Five years have passed since the operation, and the patient is alive without recurrence.
Conclusion
We encountered a case of gastric carcinoma in which poorly differentiated adenocarcinomas expanded extensively. All lesions were intramucosal.
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