Increased Akt and phosphorylated Akt expression are associated with malignant biological features of prostate cancer in Japanese men.
OBJECTIVE
To investigate the relationship between the expression of Akt (a serine/threonine kinase that plays a central role in tumorigenesis), phosphorylated Akt (p-Akt), prostate cancer tumour grade, androgen receptor (AR)-staining score, and Ki67 labelling index (LI) in Japanese men.


METHODS
The expression and activation of the cell survival protein Akt was analysed by immunohistochemical staining of paraffin-embedded tissue microarray sections of prostate carcinoma taken from 52 Japanese men who under radical prostatectomy. The correlation between the expression of Akt and p-Akt, and their relationship to primary Gleason grade, AR expression and Ki-67 LI was investigated.


RESULTS
The expression of Akt and p-Akt were positively related to primary Gleason grade (Fisher's exact test, P = 0.002 and P = 0.032, respectively). Both AR-staining score and Ki67 LI were were positively related to the expression of Akt (both P < 0.001) and p-Akt (P < 0.001 and P = 0.008, respectively). There was a significant positive correlation between the expression of Akt and p-Akt (Spearman's correlation, r = 0.644, P < 0.001).


CONCLUSIONS
Increased expression of both Akt and p-Akt were associated with higher tumour grade as well as a higher AR-staining score and Ki67 LI. These data indicate that Akt and p-Akt might be molecular markers for detecting malignant biological features of prostate cancer in the Japanese population.
Shimizu
Yousuke
Y
Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Segawa
Takehiko
T
Inoue
Takahiro
T
Shiraishi
Taizo
T
Yoshida
Toru
T
Toda
Yoshinobu
Y
Yamada
Tomomi
T
Kinukawa
Naoko
N
Terada
Naoki
N
Kobayashi
Takashi
T
Kinoshita
Hidefumi
H
Kamoto
Toshiyuki
T
Nakamura
Eijiro
E
Ogawa
Osamu
O
D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D018572:Disease-Free Survival; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D015999:Multivariate Analysis; D010766:Phosphorylation; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011944:Receptors, Androgen / Q000378:metabolism*
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D011944:Receptors, Androgen; D051057:Proto-Oncogene Proteins c-akt; D017430:Prostate-Specific Antigen