Expression and mutation of cancer suppressor gene ING1 in colorectal cancers

Ziqiang WANG; Yanhong ZHOU; Zhimin CAI; Peiwu YU

ABSTRACT

BACKGROUND:

Overexpression of cancer suppressor gene ING1 may cause apoptosis of many kinds of cancer cells and results in cell cycle arrest in G1 stage. ING1 is involved in p53 signaling pathway and regulates the activity of p53 as a transcription-activating factor.

OBJECTIVE:

To explore the association of ING1 gene expression and mutation with the clinicpathological features of colorectal cancer.

DESIGN:

A controlled observation of the pathological samples.

SETTING:

Department of General Surgery, Southwest Hospital, Third Military Medical University of Chinese PLA.

PARTICIPANTS:

Totally 52 fresh colorectal cancer samples were obtained from patients hospitalized in the Southwest Hospital, Third Military Medical University of Chinese PLA from October 1998 to October 1999. Normal mucosal tissues were also collected 10 cm from the margin of the tumor during the operation. The patients included 29 male and 23 female patients with an average age of 50.28 years.

METHODS:

ING1mRNA and protein expressions were detected in the 52 colorectal cancer tissue samples. The ING1 gene mutation was detected by analyzing single-stranded DNA polymorphism. The expression of p53 protein in the colorectal cancer tissue was detected immunohistochemically.tion-single-strand conformation polymorphism.was obviously decreased in comparison with that in the normal mucosa(0. 626 ±0. 382 vs 1. 166 ±0. 245, P ＜ 0. 001) . The expression of ING1 in the tumor tissue of patients with lymphatic metastasis was significantly lower than that in the tumor tissues from patients without lymphatic metastasis (0. 393 ±0. 243 vs 0. 960 ±0. 299, P ＜0.01). The expression of p53 protein was positively correlated with ING1 mRNA expression( P ＜ 0.01). Only one of the 52 samples was positive for ING1 gene mutation.

CONCLUSION:

ING1 gene may participate in the occurrence and progression of colorectal cancer and its decreased expression inhibits the action of tumor suppressor genes. The decrement in ING1 mRNA and protein expression without gene mutation indicates that ING1 participates in the pathogenesis of colorectal cancer in a manner quite different from that of the classic tumor suppressor genes.