Immunohistochemical analysis of S6K1 and S6K2 localization in human breast tumors.
OBJECTIVE
To perform an immunohistochemical analysis of human breast adenomas and adenocarcinomas as well as normal breast tissues in respect of S6 ribosomal protein kinase (S6K) expression and localization in normal and transformed cells.


METHODS
The expression level and localization of S6K have been detected in formalin fixed, paraffin embedded sections of normal human breast tissues, adenomas and adenocarcinomas with different grade of differentiation. Immunohistochemical detection of S6K1 and S6K2 in normal human breast tissues and breast tumors were performed using specific monoclonal and polyclonal antibodies against S6K1 and S6K2 with following semiquantitative analysis.


RESULTS
The increase of S6K content in the cytoplasm of epithelial cells in benign and malignant tumors has been detected. Nuclear accumulation of S6K1 and to a greater extend S6K2 have been found in breast adenocarcinomas. About 80% of breast adenocarcinomas cases revealed S6K2 nuclear staining comparing to normal tissues. In 31% of cases more then 50% of cancer cells had strong nuclear staining. Accumulation of S6K1 in the nucleus of neoplastic cells has been demonstrated in 25% of cases. Nuclear localization of S6K in the epithelial cells in normal breast tissues has not been detected.


CONCLUSIONS
Immunohistochemical analysis of S6K1 and S6K2 expression in normal human breast tissues, benign and malignant breast tumors clearly indicates that both kinases are overexpressed in breast tumors. Semiquantitative analysis of peculiarities of S6K localization in normal tissues and tumors revealed that nucleoplasmic accumulation of S6K (especially S6K2) is a distinguishing feature of cancer cells.
Filonenko
Valeriy V
VV
Institute of Molecular Biology and Genetic, NAS of Ukraine, Kyiv, Ukraine. aniko@a-teleport.com
Tytarenko
Ruslana
R
Azatjan
Sergey K
SK
Savinska
Lilya O
LO
Gaydar
Yuriy A
YA
Gout
Ivan T
IT
Usenko
Vasiliy S
VS
Lyzogubov
Valeriy V
VV
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000236:Adenoma / Q000235:genetics* / Q000473:pathology; D000911:Antibodies, Monoclonal; D001940:Breast / Q000502:physiology; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D019893:Ribosomal Protein S6 Kinases / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics
D000911:Antibodies, Monoclonal; D019893:Ribosomal Protein S6 Kinases