Hence, GALNT3 suppression could inhibit cell proliferation and invasion/ migration by destabilizing MUC1 and possibly other mucin-type glycoproteins and thus inducing the expression of cell adhesion proteins, although further in-depth analysis will be required to elucidate the precise mechanism of the GALNT3-MUC1 pathway in EOC cells. Our data specify some of the putative mechanisms of abnormal glycosylation in ovarian carcinogenesis and the identification of the GALNT3 enzyme as novel EOC biomarker and/or possible molecular target for EOC therapy. Further studies are needed to more completely elucidate the functional implications of GALNT3 and possibly, of other members of the GALNAC-Ts gene family in ovarian tumorigenesis. METHODS Patients and tissue specimens Snap Aphrodine site frozen 
and formalin-fixed paraffin-embedded tissues of 117 EOC tumors were obtained at the Hotel-Dieu de Quebec Hospital, Quebec, Canada. These included 13 borderline, or LMP tumors and 104 HG adenocarcinomas. None of the patients received CT before surgery. All tumors were histologically classified according to the criteria defined by the World Health Organization. The CT treatment was completed for all patients and the response to treatment was known. Disease progression was evaluated following the PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19861045 guidelines of the Gynecology Cancer Intergroup. Progression free survival was defined as the time from surgery to the first observation of disease progression, recurrence or death. Thirteen normal ovarian samples were derived from women subjected to hysterectomy with oophorectomy due to non-ovarian pathologies. The study was approved by the Clinical Research Ethics Committee of the Hotel-Dieu de Quebec Hospital and all patients signed an informed consent for voluntary participation. Cell cultures The EOC cell lines OVCAR3 and SKOV3 were purchased from American Tissue Type Collection; OV-90, OV2008, TOV-112 and TOVOncotarget 21 cell lines were a kind gift from Dr. Anne-Marie Mes-Masson, while A2780s and A2780cp cell lines were a kind gift 
from Dr. Benjamin Tsang. The cell lines were passed in different culture media supplemented with 10% fetal bovine serum, as described previously. Bisulfite sequencing PCR analysis BSP analysis was performed, as previously described. Briefly, genomic DNAs from normal ovarian tissues, borderline, grade 1 and grade 3 EOC tumor specimens were isolated using the Qiagen PG 490 DNeasy Blood and Tissue Kit. Bisulfite modification of genomic DNAs was done using the Methyl Detector kit. For BSP, a 315-bp fragment was amplified using primer pairs specific for bisulfitemodified sequences but not harboring CpGs, located at nt + 304 to nt + 619 downstream of the GALNT3 transcription start codon. BSP primer selection was performed using the Methyl Primer Express Software v1.0. PCR was done for 30 cycles. PCR products were sent for dideoxy-sequencing analysis at the Genomics Analysis Platform at Laval University. counterstained with hematoxylin. GALNT3 protein expression was assessed by semiquantitative scoring of the intensity of staining and recorded as absent, weak, moderate or strong. The relationship between GALNT3 expression in serous ovarian carcinomas and normal ovarian tissues was evaluated by the Wilcoxon two-sample test. A significant association was considered when p-value was below 0.05. A Kaplan-Meier curve and the log-rank test were performed based on PFS values to test the effect of the intensity of GALNT3 on disease progression.A2780s cells were sta.Hence, GALNT3 suppression could inhibit cell proliferation and invasion/ migration by destabilizing MUC1 and possibly other mucin-type glycoproteins and thus inducing the expression of cell adhesion proteins, although further in-depth analysis will be required to elucidate the precise mechanism of the GALNT3-MUC1 pathway in EOC cells. Our data specify some of the putative mechanisms of abnormal glycosylation in ovarian carcinogenesis and the identification of the GALNT3 enzyme as novel EOC biomarker and/or possible molecular target for EOC therapy. Further studies are needed to more completely elucidate the functional implications of GALNT3 and possibly, of other members of the GALNAC-Ts gene family in ovarian tumorigenesis. METHODS Patients and tissue specimens Snap frozen and formalin-fixed paraffin-embedded tissues of 117 EOC tumors were obtained at the Hotel-Dieu de Quebec Hospital, Quebec, Canada. These included 13 borderline, or LMP tumors and 104 HG adenocarcinomas. None of the patients received CT before surgery. All tumors were histologically classified according to the criteria defined by the World Health Organization. The CT treatment was completed for all patients and the response to treatment was known. Disease progression was evaluated following the PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19861045 guidelines of the Gynecology Cancer Intergroup. Progression free survival was defined as the time from surgery to the first observation of disease progression, recurrence or death. Thirteen normal ovarian samples were derived from women subjected to hysterectomy with oophorectomy due to non-ovarian pathologies. The study was approved by the Clinical Research Ethics Committee of the Hotel-Dieu de Quebec Hospital and all patients signed an informed consent for voluntary participation. Cell cultures The EOC cell lines OVCAR3 and SKOV3 were purchased from American Tissue Type Collection; OV-90, OV2008, TOV-112 and TOVOncotarget 21 cell lines were a kind gift from Dr. Anne-Marie Mes-Masson, while A2780s and A2780cp cell lines were a kind gift from Dr. Benjamin Tsang. The cell lines were passed in different culture media supplemented with 10% fetal bovine serum, as described previously. Bisulfite sequencing PCR analysis BSP analysis was performed, as previously described. Briefly, genomic DNAs from normal ovarian tissues, borderline, grade 1 and grade 3 EOC tumor specimens were isolated using the Qiagen DNeasy Blood and Tissue Kit. Bisulfite modification of genomic DNAs was done using the Methyl Detector kit. For BSP, a 315-bp fragment was amplified using primer pairs specific for bisulfitemodified sequences but not harboring CpGs, located at nt + 304 to nt + 619 downstream of the GALNT3 transcription start codon. BSP primer selection was performed using the Methyl Primer Express Software v1.0. PCR was done for 30 cycles. PCR products were sent for dideoxy-sequencing analysis at the Genomics Analysis Platform at Laval University. counterstained with hematoxylin. GALNT3 protein expression was assessed by semiquantitative scoring of the intensity of staining and recorded as absent, weak, moderate or strong. The relationship between GALNT3 expression in serous ovarian carcinomas and normal ovarian tissues was evaluated by the Wilcoxon two-sample test. A significant association was considered when p-value was below 0.05. A Kaplan-Meier curve and the log-rank test were performed based on PFS values to test the effect of the intensity of GALNT3 on disease progression.A2780s cells were sta.