Plasma DNA methylation of p16 and shp1 in patients with B cell non-Hodgkin lymphoma

Background Early diagnosis and treatment of non-Hodgkin lymphoma (NHL) are progressively important. It has been shown that aberrant promoter methylation contributes to the development and progression of lymphoma. We tried to explore the effect of methylation of p16 and shp1 genes in plasma in the diagnosis of B-NHL patients. Methods The methylation of p16 and shp1 genes in plasma were detected by methylation specific polymerase chain reaction in 103 patients with B-NHL, and compared with peripheral blood leukocytes (PBLs) and formaldehydefixed paraffin-embedded (FFPE) tumor tissues. Results The results showed that methylation frequency of p16 in plasma, PBLs, and FFPE tumor tissues of newly diagnosed B-NHL patients were 37% (27/73), 16% (12/73) and 39% (16/41), whereas those of shp1 were 47% (34/73), 25% (18/73) and 63% (26/41). High methylation consistency of p16/shp1 between plasma and FFPE tumor tissues were revealed (the values of kappa: 0.84, 0.80). Moreover, there were a higher frequency of methylated p16 in all three samples in patients with B symptoms and lower platelet count (< 100 x 10(9)/L), as well as in patients with stage III/ IV in plasma and FFPE tumor tissues. Meanwhile, higher frequency of methylated shp1 was observed in patients with higher LDH level in all three samples. Conclusion Methylation of p16/shp1 in plasma can represent their methylation status in tumor tissues, and may be promising biomarkers in early diagnosis and prognosis evaluation in B-NHL.