nm23-H1 expression and loss of heterozygosity in colon adenocarcinoma.
BACKGROUND
The discovery that genetic alterations in oncogenes and tumour suppressor genes accompany tumour formation in many human tumours has encouraged the search for genes that promote or suppress tumour spread and metastasis; nm23 is a promising candidate for a metastasis suppressing gene.


OBJECTIVE
To evaluate whether expression of nm23-H1 protein or loss of heterozygosity (LOH) of the nm23-H1 gene is associated with colon cancer progression.


METHODS
Paraffin wax embedded tissue sections were analysed immunohistochemically. DNA isolated from normal and tumour tissue was used for LOH analysis using a variable nucleotide tandem repeat (VNTR) marker located in the untranslated 5' region of the nm23-H1 gene. RNA isolated from tumour and normal tissue was used for "real time" RT-PCR.


RESULTS
Of 102 adenocarcinomas examined, 58.8% stained weakly for nm23-H1 protein. There was a negative correlation between nm23-H1 positivity and tumour histological grade. In VNTR analysis, 70.2% of patients were informative and 27.4% of tumours had nm23-H1 LOH. There was a positive correlation between nm23-H1 LOH and both tumour histological grade and Dukes's stage. Expression of nm23-H1 mRNA was increased in 22 of 30 colon tumours compared with normal tissue. No significant correlation was found between nm23-H1 mRNA expression and histological grade or Dukes's stage of tumours.


CONCLUSIONS
These findings suggest that nm23-H1 protein expression in early stages may have a role in suppressing metastasis in sporadic colon cancer, whereas at a later stage both reduced nm23-H1 protein expression and LOH of the nm23-H1 gene may play role in colon cancer progression and metastasis.
Kapitanović
S
S
Division of Molecular Medicine, Rudjer Bosković Institute, HR-10000 Zagreb, Croatia. kapitan@irb.hr
Cacev
T
T
Berković
M
M
Popović-Hadzija
M
M
Radosević
S
S
Seiwerth
S
S
Spaventi
S
S
Pavelić
K
K
Spaventi
R
R
D000230:Adenocarcinoma / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D003110:Colonic Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D016147:Genes, Tumor Suppressor / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D019656:Loss of Heterozygosity / Q000235:genetics*; D008297:Male; D054778:NM23 Nucleoside Diphosphate Kinases; D009367:Neoplasm Staging; D009701:Nucleoside-Diphosphate Kinase / Q000032:analysis*; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D016019:Survival Analysis
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D054778:NM23 Nucleoside Diphosphate Kinases; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C517938:NME1 protein, human; D009701:Nucleoside-Diphosphate Kinase