Objective: To determine the general markers for the diagnosis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and select optimal cases to be interfered in early stage.
Methods: To investigate the changes of histology, Ki-67 expression, monoclonality of IgH gene rearrangement in gastric lymphoid hyperplasia (GLH) cases before and after Helicobacter pylori (Hp) eradication treatment. Histological changes were classified according to Isaacson's criteria of GLH; L26, UCHL-1, anti-Kappa, anti-Lambda and Ki-67 were applied for immunohistochemical staining; semi-nest PCR was used to detect IgH gene rearrangement.
Results: Thirty-one cases of GLH with predominant chronic gastritis and gastric ulcer were studied. The ratio of male to female in the 31 cases was 1.8 and the mean course 6.8 years. Twenty-nine cases had Hp infection. Most of the cases belonged to histological grade II and III. Only 1 case had lambda light chain restriction and 10 cases had monoclonal IgH gene rearrangement. Expression of Ki-67 and monoclonal IgH gene rearrangement were significantly increased with the crescendo of lymphoid hyperplasia grading (P < 0.05). 28 cases were given antibiotics with eradication of Hp in 24 cases and 2 cases had to be given another course of treatment. These cases were followed-up on average for 4.6 months. 18 cases showed complete regression both histologically and endoscopically, 4 cases partial regression and 6 cases no change. Four cases with histological grade II, III had the decrease of expression of Ki-67 and reversed to polyclonal IgH gene rearrangement, while there was no change in 4 cases with histological grade IV.
Conclusions: General considerations of histology, expression of Ki-67 and combined clonality of IgH gene rearrangement help to screen cases which need intervention early and make a diagnosis of gastric MALT lymphoma in early stage. Monoclonal IgH gene rearrangement in cases with histological grade III or IV appears to carry more clinical significance.