[Study on genetic aberrations of ocular mucosa-associated lymphoid tissue lymphomas occurring in southern China]

To study the genetic aberrations of ocular extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) type occurring in patients from southern China.

Fifty seven paraffin-embedded ocular MALT lymphoma specimens from patients in southern China were studied by interphase fluorescence-in-situ hybridization (FISH) for genetic aberrations including t(11;18)(q21;q21)/API2-MALT1, t(1;14)(p22;q32)/IgH-bcl-10, t(14;18) (q32;q21)/IgH-MALT1 and bcl-6/FOXP1 gene translocations.

Amongst the 57 cases studied, 9 cases (15.8%) showed chromosome translocations, including 4 cases (7.0%) of t(11;18)(q21;q21)/API2-MALT1, 1 case (1.8%) of t(14;18) (q32;q21)/IgH-MALT1, 1 case (1.8%) of bcl-6 gene-related chromosome translocation and 3 cases (5.3%) of IgH-unknown translocation partner. FISH revealed 17 cases (29.8%) with 3 copies of bcl-6 gene, 21 cases (36.8%) with 3 copies of MALT1 gene and 12 cases (21.1%) with 3 copies of both genes.

The MALT lymphoma-associated chromosome translocations t(11;18)(q21;q21)/API2-MALT1 and t(14;18) (q32;q21)/IgH-MALT1 are demonstrated in ocular MALT lymphomas of southern Chinese patients. The prevalence is significantly different from that reported in northern Chinese and northern American patients, indicating a geographic heterogeneity in the MALT lymphoma-associated genetic aberrations. The presence of 3 copies of bcl-6 and MALT1 genes is the commonest genetic abnormalities observed in ocular MALT lymphomas, suggesting a possible role in MALT lymphomagenesis.