Helicobacter pyloriInfection, Chronic Inflammation, and Genomic Transformations in Gastric MALT Lymphoma

Abstract

Nowadays, it is believed that the main role in the development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma plays Helicobacter pylori infection. This world-wide distributed bacteria is in charge of most cases of not only upper gastrointestinal tract disorders but also some of extragastric problems. Constant stimulation of the immune system causes a B-lymphocytes proliferation, which is considered to be responsible for the neoplastic transformation. On the other hand, there are 10%–20% of patients who do not respond to Helicobacter pylori eradication treatment. This group has often a chromosome translocation, which suggests that there is another unknown, so far, pathogenetic mechanism of MALT lymphoma. Majority of genetic abnormalities are connected with nuclear factor-κB (NF-κB) pathway, which activates the uncontrolled proliferation of neoplastic cells. Translocations already described in studies are t(11;18)(q21;q21), which is the most common, t(14;18)(q32;q21), t(14;18)(q32;q21), and t(3;14)(p14.1;q32). This non-Hodgkin's lymphoma is an indolent type originated outside lymph nodes. In more than 50% of cases, it occurs in the stomach. Occasionally, it can be found in salivary and thyroid gland, lung, breast, bladder, skin, or any other place in the human body. This paper is a review of the current knowledge on etiology, pathogenesis, treatment, and follow-up of gastric MALT lymphoma.

The importance of Helicobacter pylori in the development of gastric MALT lymphoma — induction of proliferation and immune suppression

“…MALT lymphomas can affect the majority of human body organs including lungs, thyroid gland, breast, urinary bladder and skin [5]. MALT lymphomas are most commonly found in the digestive system, particularly the stomach, which are defined as gastric MALT lymphomas (GML) [6].…”

“…Other detected translocations, t(14;18)(q32;q21) and t(3;14) (p14;q32), are rare and their significance has not yet been defined precisely [12]. The most frequent chromosomal aberration is the t(11;18) translocation which is detected in approximately 20% of patients with MALT lymphoma, particularly those with MALT lymphomas located in the stomach, colon and lung [5].…”

“…Based on numerous epidemiological and microbiological studies H. pylori is believed to be responsible for GML progression [5,6]. In a study on 110 patients with GML, H. pylori infection was detected in 101 (92%) cases [14].…”

“…The diagnosis should be based on invasive and noninvasive tests including measuring IgG, IgM, IgA antibodies, monoclonal stool antigens detection, the 13 C-urea breath test, microbes culture and histochemical testing [39]. H. pylori eradication therapy should rely on highly effective antibiotics with due consideration given to possible resistance in bacterial strains [5]. Approximately 20% of H. pylori strains are proved to be clarithromycin resistant.…”

“…large B-cell lymphoma (DLBCL), systemic polychemotherapy is recommended for first-line treatment despite the coexisting H. pylori infection. Patients therapy whenever advanced-stage disease occurs and in those with confirmed lymphoma recurrence is based on chlorambucil, fludarabine and rituximab treatment [5,7,9,41].…”