| Gastrointestinal mucosa-associated lymphoma is a non-lymph node-derived mucosa- associated tumor. With the development of biomedicine, pathology, immunology, and molecular genetics, gastrointestinal mucosa-associated lymphoma has been definitely defined as a special type of lymphoma: non-lymph node-derived B-cell lymphoma with marginal zone cell differentiation, phenotype, and low malignancy in tissues such as mucosa and glands, i.e. mucosa-associated lymphoid tissue lymphoma, which is essentially B-cell lymphoma at the marginal zone in the follicles. Lymphomas in gastrointestinal tract are the common parts involved by non-lymph node-derived lymphoma. MALT-lymphoma, amounting to 1/3 of lymphomas in the gastrointestinal tract, ranks second in tumors of the gastrointestinal tract. It is reported by foreign researchers that the occurrence of MALT-lymphoma amounts to 5%, 17%, and 5% of gastric carcinoma, small intestinal carcinoma, and large intestinal carcinoma respectively. With the changes of the living environment of human beings, the occurrence of this kind of tumor increases annually. Various types of lymphomas and complicated classifications (small B-cell lymphoma includes 7 categories) make it difficult to conduct pathological diagnosis of lymphomas.The genesis and progression of tumors are associated with the inhibition of cell apoptosis and the proliferative state of cells as well. Researches have indicated that cell proliferation and abnormal differentiation and irregular regulation of apoptosis synergistically result in the genesis and progression of tumors, and are associated with the treatment and prognosis. Multiple genes participate in the regulation of apoptosis.Bcl-2 gene family is the important apoptosis-regulatory genes. Overexpression of bcl-2 can be found in various human tumors such as lymphoma, neuroblastoma, breast cancer, prostatic carcinoma, malignant melanoma, etc. The relationship between bcl-2 gene, the putative anti-apoptosis gene, i.e. apoptosis-inhibiting gene, and proliferating cell nuclear antigen (PCNA), the acid non-histone protein, the objective index for reflection of the activity of cell proliferation, in the genesis and progression of tumors needs to be further studied. MALT-lymphoma in the gastrointestinal tract belongs to malignant clonal disease. The gene rearrangement of immunoglobulin is the specific manifestation of DNA during the process of B-lymphocyte differentiation. Studies of the gene rearrangement of immunoglobulin IgH and L chains can help to understand the biological and genetic behaviors of this tumor at the molecular level, which is of great clinical value in diagnosis and differential diagnosis of responsive proliferation and lymphoma, and is also significant in the correct typing of lymphomas. Till now, human has understood MALT-lymphoma at the molecular level. MALT-lymphoma, with multiple abnormal expression of protein and gene and as an independent disease, has specific morphological, immune phenotypie, and biological properties. Abnormal expression of protein and gene is one of the mechanisms of the genesis and progression of all tumors, so further studies of the expression changes of the key proteins and genes and their roles during the process of genesis and progression of MALT-lymphoma can provide theoretical proof for the diagnosis, metastasis, and prognosis of MALT-lymphoma.This study is composed of two parts for the investigation of MALT-lymphoma. Part I, histopathological study: morphological study and study of immune phenotype of the pathological sections from 60 cases of MALT-lymphoma were conducted; expressions of PCNA and apoptotic regulatory gene in MALT-lymphoma were detected by immunohistochemistry. Part II, molecular pathology: the gene rearrangement of heavy chain IgH and the expression of the restrictive expression of κ and λ light chains of the immunoglobulin were detected by polymerase chain reaction (PCR) and immuno- histochemistry, respectively. The purposes of the study include: (1) to provide proof for the clinicopatho...
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