[Prognostic value of P16 gene methylation and P16 protein expression in gastrointestinal stromal tumor].
OBJECTIVE
To study the methylation status of P16 gene promoter and the expression of P16 protein in gastrointestinal stromal tumors(GIST) and to explore the prognostic value.


METHODS
Methylation status of the P16 promoter was detected by methylation- specific polymerase chain reaction (MSP) and the expression of P16 protein by immunohistochemistry in 62 patients with GIST.


RESULTS
The status of P16 gene methylation and the expression of P16 protein were significantly different among the patients with different subclassification of GIST using Fletcher's scheme (P < 0.05, P < 0.01). And there were significant differences in progressive disease (PD) among various levels of P16 expression (P < 0.01). P16 gene methylation was closely related to P16 protein. P16 gene methylation accounted for 75% in the tumor tissue with less than 50% P16 positive cells, and accounted for only 10% in the tumor tissue with more than 50% P16 positive cells (P< 0.01).


CONCLUSIONS
P16 immunohistochemical assessment can be used as a prognostic index for GIST. The patients with more than 50% fraction of cells with low P16 immunostaining have poor prognosis.
Liang
Jian-fang
JF
Department of Pathology, The First Affiliated Hospital, Shanxi Medical Univercity, Taiyuan 030001, China. jfliang2000@yahoo.com.cn
Zheng
Hui-xia
HX
Li
Ning
N
Cheng
Cai-xia
CX
Xiao
Hong
H
Wang
Hong-kun
HK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018899:CpG Islands; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation; D005260:Female; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D055815:Young Adult
D019941:Cyclin-Dependent Kinase Inhibitor p16