title: Clinical Significance of "Double-hit" and "Double-protein" expression in Primary Gastric B-cell Lymphomas.
abstract: OBJECTIVE
  Primary gastric B-cell lymphoma is the second most common malignancy of the stomach. There are many controversial issues about its diagnosis, treatment and clinical management. "Double-hit" and "double-protein" involving gene rearrangement and protein expression of c-Myc and bcl2/bcl6 are the most used terms to describe DLBCL poor prognostic factors in recent years. However, very little is known about the role of these prognostic factors in primary gastric B-cell lymphomas. This study aims to obtain a molecular pathology prognostic model of gastric B-cell lymphoma for clinical stratified management by evaluating how the "double-hit" and "double-protein" in tumor cells as well as microenvironmental reaction of tumor stromal tissue affect clinical outcome in primary gastric B-cell lymphomas.
  
  
  METHODS
  Data and tissues of 188 cases diagnosed with gastric B-cell lymphomas were used in this study. Tumor tissue microarray (TMA) of formalin fixed and paraffin embedded (FFPE) tissues was constructed for fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) analysis with a serial of biomarkers containing MYC, BCL2, BCL6, CD31, SPARC, CD10, MUM1 and Ki-67. Modeled period analysis was used to estimate 3-year and 5-year overall survival (OS) and disease-free survival (DFS) distributions.
  
  
  RESULTS
  There was no definite "double-hit" case though the gene rearrangement of c-Myc (5.9%), bcl2 (0.1%) and bcl6 (7.4%) was found in gastric B-cell lymphomas. The gene amplification or copy gains of c-Myc (10.1%), bcl-2 (17.0%) and bcl-6 (0.9%) were present in these lymphomas. There were 12 cases of the lymphomas with the "double-protein" expression of MYC and BCL2/BCL6. All patients with "double-protein" gastric B-cell lymphomas had poor outcome compared with those without. More importantly, "MYC-BCL2-BCL6" negative group of gastric B-cell lymphoma patients had favorable clinical outcome regardless clinical stage, pathological types and therapeutic modalities. And the similar better prognosis was found in the cases with low microvessel density (MVD) in tumor tissue and high expression of SPARC (SPARC≥5%) in stromal cells.
  
  
  CONCLUSIONS
  "Double-hit" lymphoma was rare among primary gastric lymphoma, while patients with multiple gene amplification and/or copy gains of c-Myc, bcl2 and bcl6, and "double-protein" gastric B-cell lymphomas had a poor clinical outcome. In addition, patients with MYC, BCL2 and BCL6 expression negative or low MVD in tumor tissue with high expression of SPARC in stromal cells could have better prognosis than other gastric B-cell lymphomas regardless of their clinical stage and pathological types. These results would be of very importance for clinical stratified management and precision medicine of gastric B-cell lymphomas.
authors.affiliation: 1. Department of Pathology, Changhai Hospital, The Second Military Medical University, Shanghai 200433, CHINA; 2. Molecular Pathology, Cellular & Molecular Pathology Branch, National Institutes of Health, Research Triangle Park, NC 27709, USA.
authors.forename: Miaoxia
authors.initials: M
authors.lastname: He
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Keting
authors.initials: K
authors.lastname: Chen
authors.affiliation: 4. Department of Pathology, Children Hospital and Women Health Center of Shanxi, Taiyuan 030013, CHINA.
authors.forename: Suhong
authors.initials: S
authors.lastname: Li
authors.affiliation: 5. Division of Molecular Pathology, Joint Pathology Center, Washington, DC 20817, USA.
authors.forename: Shimin
authors.initials: S
authors.lastname: Zhang
authors.affiliation: 1. Department of Pathology, Changhai Hospital, The Second Military Medical University, Shanghai 200433, CHINA.
authors.forename: Jianming
authors.initials: J
authors.lastname: Zheng
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Hu
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Lei
authors.initials: L
authors.lastname: Gao
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Xianmin
authors.initials: X
authors.lastname: Song
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Weiping
authors.initials: W
authors.lastname: Zhang
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wang
authors.affiliation: 3. Department of Hematology, Changhai Hospital, The Second Military Medical University, University, Shanghai 200433, CHINA.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Yang
keywords: Double-hit; Double-protein; Fluorescent in situ hybridization; Immunohistochemistry and Tumor tissue microarray.; MVD; Primary gastric B-cell lymphoma; SPARC