Immunohistochemical analysis of Ki-67, PCNA and S6K1/2 expression in human breast cancer.
OBJECTIVE
To assess the correlation between the expression profiles of ribosomal protein S6 kinase (S6K1/2), Ki-67 nuclear antigen (Ki-67) and proliferating cell nuclear antigen (PCNA) in human breast adenocarcinomas.


METHODS
The expression pattern of S6K1/2, Ki-67 and PCNA has been investigated by immunohistochemical analysis of formalin fixed paraffin embedded sections of 40 human breast adenocarcinomas. Analysis was performed using specific monoclonal and polyclonal antibodies directed against S6K2, Ki-67 and PCNA followed by semi-quantitative measurements.


RESULTS
Positive correlation between nuclear staining for S6K2 and PCNA (p < or = 0.01) or Ki-67 (p < or = 0.01) in breast cancer cells has been detected. No significant correlation in nuclear staining was observed between S6K1 and PCNA or Ki-67. In addition, we have detected an increase in S6K2 expression in the nuclei of cancer cells localized predominantly in peripheral areas of the tumor contacting with normal tissue.


CONCLUSIONS
The accumulation of S6K2, but not S6K1, in the nuclei of cancer cells and the correlation with the expression of PCNA and Ki-67 suggest the involvement of S6K2 in the regulation of malignant growth.
R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology NAS of Ukraine, Kyiv, Ukraine.
Valeriy
V
Lyzogubov
Yulia
Y
Khozhaenko
Vasilij
V
Usenko
Stepan
S
Antonjuk
Galina
G
Ovcharenko
Iryna
I
Tikhonkova
Valeriy
V
Filonenko
D014408:Biomarkers, Tumor / Q000378:metabolism*; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen / Q000378:metabolism*; D009367:Neoplasm Staging; D016612:Paraffin Embedding; D011379:Prognosis; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism*
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D019893:Ribosomal Protein S6 Kinases