The Study Of Chromosomal Abnormality In MALT Lymphomas Of Different Sites

Backgrounds and Aims:Variable frequencies of MALT lymphoma-associated genetic aberrations in MALT lymphomas of different sites were reported from overseas since 2003 Most of studies of MALT lymphomas in China only foused on clinical and prognostic analyses of gastric MALT lymphomas,few of them investigated their genetic aberrations.The frequencies of t(11;18)(q21;q21)API2/MALT1,t(1;14)(p22;q32)IGH/BCL10, t(14;18)(q32;q21)IGH/MALT1 as well as chromosomal translocation involved BCL6 gene are largely unknown in China.Therfore,We collected a large sum of cases ofdomestic MALT lymphomas from different sites to investigate chromosomal abnormality.Methods:153 cases of MALT lymphomas were collected from Beijing Medical University,Guangxi Medical University,The People's Hospital of Guangxi Zhuang Autonomous Region,The third Affiliated Hospital of Zhongshan Medical University,Shanxi Cancer Hospital and Guilin Medical College.Immunohistochemistry and FISH were applied to investigate chromosomal abnormaliity in MALT lymphomas of different sitesResults:In MALT lymphomas,t(11;18)(q21;q21)API2/MALT1, t(1;14)(p22;q32)IGH/BCL10,t(14;18)(q32;q21)IGH/MALT1 and chromosomal translocation involved BCL6 gene as well as trisomies 3 and 18 occurred at markedly variable frequencies in MALT lymphoma of different sites.Theses four translocations were mutually exclusive.In 153 cases MALT lymphomas, we found 40 cases(26.1%)with chromosomal translocation,25 cases (16.3%)with t(11;18)(q21;q21)API2/MALT1,only 2 cases(1.3%)and 1 cases (0.7%)showing t(1;14)(p22;q32)IGH/BCL10 and t(14;18)(q32;q21) IGH/MALT1,respectively.Chromosomal translocation involved BCL6 gene was found in 3 cases(2.0%)MALT lymphomas.Frequencies of trisomies 3 and 18 were 18.3%(28 cases)and 17.6%(27 cases),respectively.We also identified IGH/unknown partner in 9 cases(5.9%).Our results demonstrated that chromosomal translocation in MALT lymphomas occurred most frequently in lung(67%),followed by stomach(21%),salivary gland(20%),intestines(17.4%) and ocular adnexae(12.5%).Conclusion:This is the first study of translocation frequency and anatomic site specificity using FISH in a large sum of MALT lymphomas derived from mainland Chinese patients.The results show(1)In MALT lymphomas,t(11;18)(q21;q21)API2/MALT1,t(1;14)(p22;q32)IGH/BCL10, t(14;18)(q32;q21)IGH/MALT1 and chromosomal translocation involved BCL6 gene occur at markedly variable frequencies in MALT lymphoma of different anatomic sites.(2)The frequencies of trisomies 3 and 18 also are variable in MALT lymphoma of different anatomic sites.(3)The results of our study are approximately similar to other reports from overseas.