Related Experiment Video
Updated: Mar 20, 2026
Comprehensive DNA Methylation Analysis Using a Methyl-CpG-binding Domain Capture-based Method in Chronic Lymphocytic Leukemia Patients
Published on: June 16, 2017
Variable Expression and Hypermethylation of p16 Gene in Patients with T-ALL and Cell Lines
Abstract:
The multi tumor suppressor genes MTS1 (CDKN2, p16INK4A) and MTS2 (CDKN1, p15INK4B) located at 9p21-22 are inactivated in some human cancers via several mechanisms including deletion and hypermethylation. In hematological malignancies, deletion of p16/p15 locus has been shown to be highly specific to lymphoid malignancies, and more particularly to T-cell acute lymphoblastic leukemia (TALL). We have investigated the deletion, methylation and p16 protein expression status of MTS1 in Tcell childhood acute lymphoblastic leukemia (19 cases) and cell lines[11]. On Southern blot homozygous deletions or hemizygous deletion with rearangement were detected in 4/19 T-ALL. The expression of p16 protein was not observed on Western blot in 4/15 T-ALL with intact p16 gene. The p16 gene was methylated 3/15 in T-ALL. Only one of three expressed p16 protein. The other 11/15 T-ALL had p16 protein expression but different level. Loss of MTS1 was observed in 3/11 cell lines. Cell line with MTS1 gene had p16 protein expression in 6/8. After treatment with the demethylating agent (5-AzoCyt) RD cell line showed p16 expression. This has not been observed with the other cell lines. Thus hypermethylation of MTS1 is rare in childhood T-ALL. Although inactivation of MTS1 by deletion is common in T-ALL and cell lines. Furthermore our data show that the p16 gene inactivation by hypermethylation and deletion may play a role in the leukemogenesis.
Insights
Inactivation of the MTS1 tumor suppressor gene via deletion is common in childhood T-cell acute lymphoblastic leukemia (T-ALL). Hypermethylation of MTS1 is rare, but both mechanisms can contribute to leukemogenesis.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Multi tumor suppressor genes MTS1 (p16INK4A) and MTS2 (p15INK4B) at 9p21-22 are crucial in preventing cancer.
- These genes are inactivated through deletion or hypermethylation in various human cancers.
- Deletion of the p16/p15 locus is particularly specific to lymphoid malignancies, especially T-cell acute lymphoblastic leukemia (T-ALL).
Purpose of the Study:
- To investigate the status of deletion, methylation, and p16 protein expression of the MTS1 gene in childhood T-ALL.
- To understand the role of MTS1 inactivation mechanisms in T-ALL development.
Main Methods:
- Southern blot analysis to detect gene deletions.
- Western blot analysis to assess p16 protein expression.
- Methylation analysis of the p16 gene.
- Treatment with a demethylating agent (5-Aza-CdR) to assess the impact of methylation.
Main Results:
- Homozygous or hemizygous deletions of MTS1 were found in 4 out of 19 T-ALL cases.
- p16 protein expression was absent in 4 out of 15 T-ALL cases with an intact p16 gene.
- The p16 gene was methylated in 3 out of 15 T-ALL cases, with only one case showing p16 protein expression.
- MTS1 loss occurred in 3 out of 11 cell lines, and p16 protein was expressed in 6 out of 8 cell lines with an intact MTS1 gene.
- Demethylation treatment induced p16 expression in the RD cell line, suggesting hypermethylation is rare but can inactivate MTS1.
Conclusions:
- MTS1 inactivation by deletion is a frequent event in childhood T-ALL.
- Hypermethylation of MTS1 is a rare mechanism in childhood T-ALL.
- Both deletion and hypermethylation of MTS1 may contribute to leukemogenesis in T-ALL.
