Gene expression profiling of gastric cancer by microarray combined with laser capture microdissection.
OBJECTIVE
To examine the gene expression profile of gastric cancer (GC) by combination of laser capture microdissection (LCM) and microarray and to correlate the profiling with histological subtypes.


METHODS
Using LCM, pure cancer cells were procured from 45 cancerous tissues. After procurement of about 5000 cells, total RNA was extracted and the quality of RNA was determined before further amplification and hybridization. One microgram of amplified RNA was converted to cDNA and hybridized to cDNA microarray.


RESULTS
Among 45 cases, only 21 were qualified for their RNAs. A total of 62 arrays were performed. These included 42 arrays for cancer (21 cases with dye-swab duplication) and 20 arrays for non-tumorous cells (10 cases with dye-swab duplication) with universal reference. Analyzed data showed 504 genes were differentially expressed and could distinguish cancerous and non-cancerous groups with more than 99% accuracy. Of the 504 genes, trefoil factors 1, 2, and 3 were in the list and their expression patterns were consistent with previous reports. Immunohistochemical staining of trefoil factor 1 was also consistent with the array data. Analyses of the tumor group with these 504 genes showed that there were 3 subgroups of GC that did not correspond to any current classification system, including Lauren's classification.


CONCLUSIONS
By using LCM, linear amplification of RNA, and cDNA microarray, we have identified a panel of genes that have the power to discriminate between GC and non-cancer groups. The new molecular classification and the identified novel genes in gastric carcinogenesis deserve further investigations to elucidate their clinicopathological significance.
Wu
Ming-Shiang
MS
Department of Internal Medicine and Primary Care Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan, China.
Lin
Yi-Shing
YS
Chang
Yu-Ting
YT
Shun
Chia-Tung
CT
Lin
Ming-Tsan
MT
Lin
Jaw-Town
JT
D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007834:Lasers; D042282:Microdissection; D020411:Oligonucleotide Array Sequence Analysis; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology*