Polo-like kinase: a novel marker of proliferation: correlation with estrogen-receptor expression in human breast cancer.
Previous data have shown that the mRNA-expression of the serin/threonine-kinase polo-like kinase (PLK) is closely correlated with the survival of patients suffering from a subset of malignant tumors. PLK-mRNA and protein-expression are restricted to cells in the cell cycle. PLK-mRNA-transcripts are highly abundant in proliferating cells; no gene expression is found in G0-phase cells. Here we investigated the mRNA- and protein-expression of PLK- and estrogen-receptor (ER) in human breast-carcinoma by northern-blotting, RT-PCR and immunohistochemistry. The expression of MIB-I was determined on serial sections. Analysis of the immunohistochemical data revealed a close correlation between the ER and PLK-expression (r = 0.677; p = 0.001, n = 30). No relationship between the mRNA-expression of ER and PLK was found. Furthermore, no correlation for the protein expression of PLK and MIB-I exists. The influence of estrogen (ES) is known to have proliferative potential. The expression of ER correlates with the ES-plasma-level. In addition, the hormone cycle of premenopausal women undergoes rapid vacillations with varying effects on the proliferating tumor cells, e.g., growth induction. Our results therefore show that ER-expression is not only of therapeutic value for the clinician, but it may also be a tool for determining the tumor proliferation index more precisely by integrating the hormone-mediated proliferation stimulus.
Wolf
G
G
Pathologisches Institut, Ruprecht-Karls-Universität Heidelberg, Universitätsklinikum Mannheim, Germany. WGeorg8912@aol.com
Hildenbrand
R
R
Schwar
C
C
Grobholz
R
R
Kaufmann
M
M
Stutte
H J
HJ
Strebhardt
K
K
Bleyl
U
U
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor / Q000032:analysis; D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000556:secondary; D018275:Carcinoma, Lobular / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000556:secondary; D018797:Cell Cycle Proteins; D002455:Cell Division; D005260:Female; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D008875:Middle Aged; D009687:Nuclear Proteins / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D011960:Receptors, Estrogen / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097869:Polo-Like Kinase 1
D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011960:Receptors, Estrogen; D000097869:Polo-Like Kinase 1