1075P - Detection of CAGA expression in gastric mucosa-associated lymphoid tissue lymphoma-biologic significance and clinical implication

Date 30 September 2012
Event ESMO Congress 2012
Session Poster presentation II
Topics Lymphomas
Translational Research
Presenter Sung-Hsin Kuo
Authors S. Kuo1, L. Chen2, C. Lin3, M. Wu4, P. Hsu4, Y. Tzeng5, H. Tsai2, H. Wang4, K. Yeh6, A. Cheng5
  • 1Department Of Oncology, National Taiwan University Hospital, 100 - Taipei/TW
  • 2National Institute Of Cancer Research, National Health Research Institutes, TW-704 - Tainan/TW
  • 3Departments Of Pathology, National Taiwan University Hospital, 100 - Taipei/TW
  • 4Departments Of Internal Medicine, National Taiwan University Hospital, 100 - Taipei/TW
  • 5Departments Of Oncology, National Taiwan University Hospital, 100 - Taipei/TW
  • 6Oncology Dept., National Taiwan University Hospital, 100 - Taipei/TW

Abstract

Background

We recently reported that a direct contact of Helicobacter pylori (HP) with B cells resulted in CagA translocation into the cells (Cancer Res 2010;70:5740-8). The translocated CagA further activates extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), and up-regulates the expressions of Bcl-2 and Bcl-xL. In this study, we sought to verify if CagA exists in the malignant B cells of gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

Methods

Expression of CagA protein, phospho-SHP-2, phospho-ERK, phospho-p38MAPK, Bcl-2 and Bcl-xL in a series of 26 gastric MALT lymphoma was determined by immunohistochemistry. Western blot analysis was done to confirm immunohistochemical detection of CagA and biopsies from non-gastric MALT lymphoma served as negative controls. The association of CagA expression and the tumor response to HP-eradication (HPE) therapy was evaluated in 77 stage IE/IIE1 low-grade gastric MALT lymphoma patients.

Results

The expression of CagA was detected in 35 (45.5%) of 77 patients. CagA expression was closely associated with the expression phospho-SHP-2 (P = .016), phospho-ERK (P < .001), phospho-p38MAPK (P = 0.014), Bcl-2 (P = 0.009), and Bcl-xL (P = 0.008). CagA expression was detected in 30 (69.8%) of 43 HP-dependent cases, and in 5 (14.7%) of 34 HP-independent cases (P < 0.001). Furthermore, patients with CagA expression responded to HPE more rapidly than those without (median time to complete remission, 3.0 months versus 7.0 months, P = 0.032).

Conclusion

CagA protein can be translocated into malignant B cells of MALT lymphoma. The expression of CagA in lymphoma cells appears to be biologically and clinically significant.

Disclosure

All authors have declared no conflicts of interest.