**9. Conclusions**

During the past two decades, we have discovered that the spectrum of *Hp*-related gastric lymphoma is much wider than was previously thought. In addition to the classical MALT lymphoma, we demonstrated that DLBCL with (DLBCL[MALT]) and without ("pure" DLBCL) histological evidence of MALT lymphoma are all closely related to *Hp*. Most importantly, they can all be cured by HPE, a clinical practice that saves thousands of lives and allows patients to avoid systemic immunochemotherapy-related adverse effects. Furthermore, we have identified the existence of *Hp* CagA in the entire spectrum of gastric lymphomas, including MALT lymphoma, DLBCL(MALT), and "pure" DLBCL; it is also important to note that CagA-regulated signaling molecules such as p-SHP-2 and p-ERK were also expressed in tumor cells of *Hp*-dependent gastric MALT lymphoma as well as of gastric DLBCLs. In addition, *Hp*-positive gastric "pure" DLBCLs, especially those exhibiting CagA expression, are not the same as *Hp*-unrelated gastric "pure" DLBCL in terms of clinicopathological manifestations and biological behavior. These findings indicate that CagA may lead to direct lymphomagenesis in these *Hp*-related gastric lymphomas via the regulation of pivotal tyrosine phosphorylation-related signal transduction. This is a big paradigm shift, since until very recently, the classical belief has been that MALT lymphoma is caused indirectly by the interaction of *Hp* with T cells. Since many DLBCLs are of GCB origin, the canonical concept that all *Hp*-related lymphomas are of a marginal-zone B cell origin, needs to be reappraised. However, we and other investigators have reported that a certain proportion of *Hp*-dependent gastric DLBCLs may be of GCB origin. These clues indicate that the spectrum of *Hp*-related gastric lymphomas should be revised to include not only MALT lymphoma, but also DLBCL(MALT) and "pure" DLBCL. Further investigations of the spectrum, lymphomagenesis, therapeutics, and cellular origins of *Hp*-related gastric lymphoma are warranted.

*Revisiting the Full Spectrum of* Helicobacter pylori*-Related Gastric Lymphoma DOI: http://dx.doi.org/10.5772/intechopen.97424*
