Down-regulation of ING4 is associated with initiation and progression of lung cancer.
OBJECTIVE
Tumour suppressor ING4 is one of ING family genes, which are involved in cell cycle arrest, gene transcription regulation, DNA repair and apoptosis. ING4 inhibition has been reported in various tumours, including gliomas, breast tumours, and stomach adenocarcinoma. The aim was to evaluate ING4 expression in lung cancers.


RESULTS
By immunohistochemistry of 246 lung tumour tissues, reduced ING4 nuclear and cytoplasmic expression were both revealed in lung cancer and associated with tumour grade. Interestingly, compared with normal tissues, we found more tumours with ING4 expression in the cytoplasm higher than in the nucleus. Nuclear ING4 inhibition correlated with the tumour stage and lymph node metastasis. Consistent with these findings, semiquantitative reverse transcriptase-polymerase chain reaction and Western blotting demonstrated decreased ING4 mRNA and expression in 100% (50/50) tumour tissues. Furthermore, ING4 expression was lower in grade III than in grades I-II tumours. Reduced ING4 mRNA correlated with lymph node metastasis.


CONCLUSIONS
Our results indicate that overall inhibition of ING4 expression and ING4 expression higher in cytoplasm than in nucleus of tumour cells may be involved in the initiation and progression of lung cancers, and thus, analysis for ING4 expression may be useful as a clinical diagnostic and prognostic tool for lung cancer.
Wang
Qiu-shi
QS
Department of Cardiothoracic Surgery, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
Li
Ming
M
Zhang
Lin-you
LY
Jin
Yan
Y
Tong
Dan-dan
DD
Yu
Yang
Y
Bai
Jing
J
Huang
Qi
Q
Liu
Fang-Li
FL
Liu
An
A
Lee
Ki-Young
KY
Fu
Song-bin
SB
D000368:Aged; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D018450:Disease Progression; D015536:Down-Regulation; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D017931:DNA Primers; D018398:Homeodomain Proteins; C483230:ING4 protein, human; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D025521:Tumor Suppressor Proteins