Adenocarcinoma of the cardia in a young man: detection of somatic p53 mutation by immunohistochemistry and automated direct sequencing

MYC, FBXW7 and TP53 copy number variation and expression in gastric cancer

BACKGROUND

MYC deregulation is a common event in gastric carcinogenesis, usually as a consequence of gene amplification, chromosomal translocations, or posttranslational mechanisms. FBXW7 is a p53-controlled tumor-suppressor that plays a role in the regulation of cell cycle exit and reentry via MYC degradation.

METHODS

We evaluated MYC, FBXW7, and TP53 copy number, mRNA levels, and protein expression in gastric cancer and paired non-neoplastic specimens from 33 patients and also in gastric adenocarcinoma cell lines. We also determined the invasion potential of the gastric cancer cell lines.

RESULTS

MYC amplification was observed in 51.5% of gastric tumor samples. Deletion of one copy of FBXW7 and TP53 was observed in 45.5% and 21.2% of gastric tumors, respectively. MYC mRNA expression was significantly higher in tumors than in non-neoplastic samples. FBXW7 and TP53 mRNA expression was markedly lower in tumors than in paired non-neoplastic specimens. Moreover, deregulated MYC and FBXW7 mRNA expression was associated with the presence of lymph node metastasis and tumor stage III-IV. Additionally, MYC immunostaining was more frequently observed in intestinal-type than diffuse-type gastric cancers and was associated with MYC mRNA expression. In vitro studies showed that increased MYC and reduced FBXW7 expression is associated with a more invasive phenotype in gastric cancer cell lines. This result encouraged us to investigate the activity of the gelatinases MMP-2 and MMP-9 in both cell lines. Both gelatinases are synthesized predominantly by stromal cells rather than cancer cells, and it has been proposed that both contribute to cancer progression. We observed a significant increase in MMP-9 activity in ACP02 compared with ACP03 cells. These results confirmed that ACP02 cells have greater invasion capability than ACP03 cells.

CONCLUSION

In conclusion, FBXW7 and MYC mRNA may play a role in aggressive biologic behavior of gastric cancer cells and may be a useful indicator of poor prognosis. Furthermore, MYC is a candidate target for new therapies against gastric cancer.

A clinicopathological study in young patients with gastric carcinoma

BACKGROUND AND OBJECTIVES

Gastric carcinoma rarely affects young patients. This study was undertaken in order to clarify the clinicopathological features and prognosis of young patients with gastric carcinoma.

METHODS

The resected 107 specimens from 105 patients younger than 30 years of age with gastric carcinoma were investigated using hematoxylin and eosin stain.

RESULTS

The male:female ratio was 1:1.6. Histologically, poorly differentiated adenocarcinoma was the most common type (94/107, 87.9%) (P < 0.001). Most tumors were located in the middle third of the stomach (P < 0.001). All patients had depressed lesions. The 5-year survival rates of early and advanced gastric carcinoma were 100% (30/30) and 23.5% (8/34), respectively.

CONCLUSIONS

Characteristic clinicopathological features in young patients, such as gender ratio, tumor location, macroscopic type, and histological type, were different from those in older ones. The prognosis of early gastric carcinoma in young patients was much better than that in older patients, although the prognosis of advanced gastric carcinoma in young patients was worse than that of older patients. These findings seem to indicate that young patients with early gastric carcinoma can tolerate radical treatments well; however, the aggressiveness of lesions are emphasized in patients with advanced gastric carcinoma.