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LASP-1 was identified as a protein following mass spectrometric analysis of phosphoproteins consequent to signaling by ErbB2 in SKOV-3 cells. It has been previously identified as an oncogene and is located on chromosomal arm 17q 0.76 Mb centromeric to ErbB2. It is expressed in serous ovarian cancer cell lines as a 40 kDa protein. In SKOV-3 cells, it was phosphorylated and was inhibited by Lapatinib and CP7274714. LASP-1 co-immunoprecipitated with ErbB2 in SKOV-3 cells, suggesting a direct interaction. This interaction and phosphorylation were independent of the kinase activity of ErbB2. Moreover, the binding of LASP-1 to ErbB2 was independent of the tyrosine phosphorylation of LASP-1. LASP-1 was neither expressed on the surface epithelium of the normal ovary nor in the fallopian tube. It was expressed in 28% of ovarian tumours (n = 101) that did not significantly correlate with other clinical factors. In tumours from patients with invasive ductal carcinoma of the breast who had ErbB2 amplification (3+), LASP-1 was expressed in 3/20 (P < 0.001). Analysis of the expression of an independent dataset of ovarian and breast tumours from TCGA showed the significant co-occurrence of ErbB2 and LASP-1 (P < 0.01). These results suggest that LASP-1 and ErbB2 interaction could be important in the pathogenesis of ovarian cancer. [ABSTRACT FROM AUTHOR]

BACKGROUND: There has been variability between laboratories in the identification of cancer stem cells (CSCs) markers for epithelial ovarian cancer (EOC). We have evaluated three new surface markers for EOC to identify CSCs precisely. METHODS: Three new putative CSCs specific surface markers CD9, CD24 and EPHA1 identified by a bioinformatics approach were evaluated in normal ovary, fallopian tube and ovarian tumours. RESULTS: The expression of CD9 alone was observed in normal ovarian surface epithelium and fallopian tube whereas CD24 and EPHA1 were not expressed (n = 5). CD24 was expressed in all tumours (N = 101) while CD9 and EPHA1 were expressed in 89 and 71 tumours, respectively. The statistical analysis showed significant correlation of the stage of the disease (p < 0.0001), type of surgery (p < 0.0001) and residual disease (p < 0.0001) with overall survival. Although expression of CD9, CD24 and EPHA1 was observed in the majority of tumours there was no significant correlation with outcome. In patients who underwent primary surgery, increased expression of CD24 significantly correlated with poor survival. The expression of CD24 was significantly reduced (p < 0.002) upon analysis of paired sections from patients prior to surgery and at interval debulking surgery (n = 16). CONCLUSION: These findings suggest that overexpression of these new markers may be useful in identifying and targeting ovarian CSCs and CD24 may be a putative CSCs marker in ovarian cancer. [ABSTRACT FROM AUTHOR]