All patients with follicular lymphoma (FL), myeloma or acute myeloid leukemia (AML) expressed p14ARF while nine of 23 patients with diffuse large B cell lymphoma (DLBCL) lost p14ARF expression.
As regards p16 methylation, we confirmed a high prevalence of p16 methylation (40%) in patients affected by MM and demonstrated that MTHFR 677CC is associated with a higher prevalence of p16 hypermethylation.
As regards p16 methylation, we confirmed a high prevalence of p16 methylation (40%) in patients affected by MM and demonstrated that MTHFR 677CC is associated with a higher prevalence of p16 hypermethylation.
Herein, we report the identification of Snk/Plk2 as a novel methylated gene in MM and show that methylation is not influenced in this CpG island or in that of a previously described methylated gene, CDKN2A, in MM.
In 32 cases of multiple myeloma and 19 cases of MGUS, significantly more frequent methylation of p16 (p = 0.001), SHP1 (p< or =0.001) and E-cadherin (p< or =0.001) genes was found in multiple myeloma than in MGUS.
It is possible that hypermethylation of the p16INK4A gene promoter contributes to progression to aggressive MM from indolent PCD, especially to extra-PC development.
Moreover low-expression CDKN2A group showed time-to-progression benefit in newly diagnosed patients (remission was 20.8 ± 3.6 months for 'low' and 8.4 ± 2.7 months for 'high' expressed group, p<0.0001) as well as in whole studied cohort of MM patients (remission was 20.8 ± 2.8 months for 'low' and 9.8 ± 1.1 months for 'high' expressed group, p<0.0001).
Of the putative tumour suppressor genes in the DAP kinase/p14/HDM2/p53/Apaf-1 apoptosis pathway, only DAP kinase is frequently methylated in MM, which is associated with gene silencing and might be of prognostic significance. p14 and Apaf-1 were not methylated in MM.
Our findings suggest methylation of TP73, ARF, p15 INK4B , and p16 INK4A as early events in the pathogenesis and development of plasma cell disorders; meanwhile, SOCS-1 methylation would be an important step in the clonal evolution from MGUS to MM.
Our results indicate that ANRIL may be involved in melphalan-mediated apoptosis via down-regulating p14ARF and subsequent p53, and that the rs2151280 polymorphism may be a potential prognostic biomarker for relapse in melphalan-treated MM patients.
p16 gene methylation was detected in 6 of 55 patients (10.9%), who were 1 patient with M2a, 1 patient with M5a, 2 patients with chronic myelogenous leukemia (CML) in blast crisis, 1 patient with progressing multiple myeloma (MM), 1 with non-Hodgkin's lymphoma (NHL) accompanied by B-ALL, respectively. p16 gene methylation correlates with adverse prognostic features.
Selective methylation was found in 19% for p16(INK4a), 36% for p15(INK4b), and 6.5% for both genes in MGUS, and frequencies were similar in MM suggesting that methylation of these genes is an early event, not associated with transition from MGUS to MM. p15(INK4b) and p16(INK4a) gene methylation might contribute to immortalization of plasma cells rather than malignant transformation in the natural history of MM.
Since the incidence and clinical implications of abnormalities of TP53, CDKN2A (encoding for p16 and p14) and MDM2 genes (chromosome 12) in multiple myeloma (MM) is not clear, we investigated allelic loss at the former two loci and gain at the latter locus in a series of 82 MM patients.
Subjects carrying the KCNQ1rs2237892T allele or the CDKN2A-2Brs2383208G/G, IGF1rs35767T/T and MADDrs7944584T/T genotypes had a significantly increased risk of MM (odds ratio (OR)=1.32-2.13) whereas those carrying the KCNJ11rs5215C, KCNJ11rs5219T and THADArs7578597C alleles or the FTOrs8050136A/A and LTArs1041981C/C genotypes showed a significantly decreased risk of developing the disease (OR=0.76-0.85).
The current meta-analysis confirms and reinforces existing findings that p15 (INK4b) and p16 (INK4a) promoter methylation may be closely implicated in the pathogenesis of MM.
The cyclin-dependent kinase inhibitor 1 (CDKN2B or p15(INK4B) ) gene lies adjacent to the tumor suppressor gene, cyclin-dependent kinase inhibitor 2 (CDKN2A), and is frequently mutated and deleted in a wide variety of tumors, including MM.