Butyrate induced apoptosis of lymphoma tumor cells and significantly up-regulated histone 3 acetylation (H3ac) level and target genes such as Fas, P21, P27.
We previously showed that p27 expression in MCL, as assessed by immunohistochemistry (IHC), does not show the usual inverse relationship to proliferate seen in most other lymphomas that do not overexpress cyclin D1.
All gastric and intestinal high-grade lymphomas revealed unmethylated status of p21 gene. p27 gene was unmethylated in all cases of low- and high-grade gastrointestinal lymphomas.
High grade lymphomas showed markedly decreased p21 expression (3.9 in Hg-NHL vs. 12 in Lg-NHL and 29 in CLL; values expressed as mRNA transcripts x 10(3), p < 0.009). mRNA and protein expression of p27 was considerably higher in CLL than in the lymphomas.
This is the first report showing that p27 expression in malignant lymphomas has independent prognostic significance, which necessitates future studies regarding its more precise biological role in lymphoid tumorogenesis.
A nonsense mutation (stop codon) that could result in expression of a truncated nonfunctional p27 protein was detected at codon 76 in one case of acute lymphomatous ATL, but not in matched normal tissues.