| REVIEW ARTICLE |
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| Year : 2018 | Volume
: 1
| Issue : 2 | Page : 37-44 |
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Aberrant expression of p14ARF in human cancers: A new biomarker?
Kazushi Inoue, Elizabeth A Fry
Department of Pathology, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA
Correspondence Address:
Kazushi Inoue
Department of Pathology, Wake Forest University Health Sciences, Winston-Salem, NC 27157
USA
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/tme.tme_24_17
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The ARF and INK4a genes are located on the same CDKN2a locus, both showing its tumor-suppressive activity. ARF has been shown to monitor potentially harmful oncogenic signalings, making incipient cancer cells undergo senescence or programmed cell death to prevent cancer. On the other hand, INK4a detects both aging and incipient cancer cell signals. The efficiency of detection of oncogenic signals is more efficient for the for the former than the latter in the mouse system. Both ARF and INK4a genes are inactivated by gene deletion, promoter methylation, frameshift, aberrant splicing although point mutations for the coding region affect only the latter. Recent studies show the splicing alterations that affect only ARF or both ARF and INK4a genes, suggesting that ARF is inactivated in human tumors more frequently than what was previously thought. The ARF gene is activated by E2Fs and Dmp1 transcription factors while it is repressed by Bmi1, Tbx2/3, Twist1, and Pokemon nuclear proteins. It is also regulated at protein levels by Arf ubiquitin ligase named ULF, MKRN1, and Siva1. The prognostic value of ARF overexpression is controversial since it is induced in early-stage cancer cells to eliminate premalignant cells (better prognosis); however, it may also indicate that the tumor cells have mutant p53 associated with worse prognosis. The ARF tumor suppressive protein can be used as a biomarker to detect early-stage cancer cells as well as advanced stage tumors with p53 inactivation.
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