cDNA expression profiling reveals elevated gene expression in cell clusters overlying focally disrupted myoepithelial cell layers: implications for breast tumor invasion.
BACKGROUND
Our previous studies revealed that a subset of mammary ductal carcinoma in situ (DCIS) contained focally disrupted myoepithelial (ME) cell layers that were predominantly overlain by estrogen receptor (ER) negative cells, which showed a substantially higher rate of cell proliferation and genetic alterations than adjacent ER positive cells within the same duct. This study attempted to assess whether these cells also had a different expression profile on tumor progression related genes.


METHODS
Consecutive sections were made from frozen tissues of 30 DCIS with focally disrupted ME cell layers and associated ER negative cell clusters. ER negative and adjacent ER positive cells within the same duct were microdissected for RNA extraction and amplification. Amplified RNA was converted to biotin-labeled cDNAs and interrogated with 'Cancer PathwayFinder' arrays.


RESULTS
Cells within each or among ER negative clusters were immunohistochemically and morphologically similar, whereas they differed substantially from adjacent cells within the same duct. Of 20-paired informative ER negative and positive cells, 15 genes were differentially expressed. Of which, 11(73.3%) were higher in ER negative, 2 (13.3%) were higher in ER positive, and 2 (13.3%) were equal in these cells (p <0.01). Of 11 up-regulated genes in ER negative cells, 8 indirectly or directly promote proliferation and progression, and 3 promote apoptosis.


CONCLUSIONS
ER negative cell clusters showed a significantly higher expressing frequency of multiple tumor progression related genes than their adjacent ER positive counterparts, suggesting that they are likely to be biologically more aggressive and have a greater potential for invasion.
Man
Yan-Gao
YG
Department of Gynecologic & Breast Pathology, Armed Forces Institute of Pathology and American Registry of Pathology, 6825 16th Street, NW, Washington, DC 20306-6000, USA. man@afip.osd.mil
Zhang
Yi
Y
Shen
Ting
T
Zeng
Xiao
X
Tauler
Jordi
J
Mulshine
James L
JL
Strauss
Brian L
BL
D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000235:genetics* / Q000473:pathology*; D018450:Disease Progression; D004847:Epithelial Cells; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D009361:Neoplasm Invasiveness / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D011960:Receptors, Estrogen
D011960:Receptors, Estrogen