Stomatin-like protein 2 is overexpressed in epithelial ovarian cancer and predicts poor patient survival.
BACKGROUND
Stomatin-like protein 2 (SLP-2, also known as STOML2) is a stomatin homologue of uncertain function. SLP-2 overexpression has been suggested to be associated with cancer progression, resulting in adverse clinical outcomes in patients. Our study aim to investigate SLP-2 expression in epithelial ovarian cancer cells and its correlation with patient survival.


METHODS
SLP-2 mRNA and protein expression levels were analysed in five epithelial ovarian cancer cell lines and normal ovarian epithelial cells using real-time PCR and western blotting analysis. SLP-2 expression was investigated in eight matched-pair samples of epithelial ovarian cancer and adjacent noncancerous tissues from the same patients. Using immunohistochemistry, we examined the protein expression of paraffin-embedded specimens from 140 patients with epithelial ovarian cancer, 20 cases with borderline ovarian tumours, 20 cases with benign ovarian tumours, and 20 cases with normal ovarian tissues. Statistical analyses were applied to evaluate the clinicopathological significance of SLP-2 expression.


RESULTS
SLP-2 mRNA and protein expression levels were significantly up-regulated in epithelial ovarian cancer cell lines and cancer tissues compared with normal ovarian epithelial cells and adjacent noncancerous ovarian tissues. Immunohistochemistry analysis revealed that the relative overexpression of SLP-2 was detected in 73.6 % (103/140) of the epithelial ovarian cancer specimens, 45.0 % (9/20) of the borderline ovarian specimens, 30.0 % (6/20) of the benign ovarian specimens and none of the normal ovarian specimens. SLP-2 protein expression in epithelial ovarian cancer was significantly correlated with the tumour stage (P < 0.001). Epithelial ovarian cancer patients with higher SLP-2 protein expression levels had shorter progress free survival and overall survival times compared to patients with lower SLP-2 protein expression levels. Multivariate analyses showed that SLP-2 expression levels were an independent prognostic factor for survival in epithelial ovarian cancer patients.


CONCLUSIONS
SLP-2 mRNA and proteins were overexpressed in epithelial ovarian cancer tissues. SLP-2 protein overexpression was associated with advanced stage disease. Patients with higher SLP-2 protein expression had shorter progress free survival and poor overall survival times. Thus, SLP-2 protein expression was an independent prognostic factor for patients with epithelial ovarian cancer.
Department of Gynecologic Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, P.R.China. 99609248@qq.com.|Present address: Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangdong, 510515, P.R. China. 99609248@qq.com.
Fei
F
Sun
Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center, 9 JinSui Road, 510623, Guangzhou, P.R. China. 576786473@qq.com.
Wen
W
Ding
Department of Pathology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, P.R.China. hejh@sysucc.org.cn.
Jie-Hua
JH
He
Department of Gynecologic Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, P.R.China. wangxj@sysucc.org.cn.
Xiao-Jing
XJ
Wang
Department of Gynecologic Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, P.R.China. mazb@sysucc.org.cn.
Ze-Biao
ZB
Ma
Department of Gynecologic Oncology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center of Cancer Medicine, 651 Dongfeng Road East, Guangzhou, 510060, P.R.China. liyf@sysucc.org.cn.
Yan-Fang
YF
Li
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D001798:Blood Proteins / Q000235:genetics* / Q000378:metabolism; D000077216:Carcinoma, Ovarian Epithelial; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D005260:Female; D015870:Gene Expression; D006801:Humans; D053208:Kaplan-Meier Estimate; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009375:Neoplasms, Glandular and Epithelial / Q000235:genetics* / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D047368:Tumor Burden
D014408:Biomarkers, Tumor; D001798:Blood Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; C406287:STOML2 protein, human