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
Basic Principles in the Management and Treatment (of cancer)
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.