Loss of basement membrane(BM)components,such as type IV collagen has been demonstrated in ovarian cancer,but the associations with other mole cules like CD44v6,involved in metastatic process of ovarian carcinoma,have not been fully analyzed.This study i nvestigates the ex-pression of type IV collagen,CD44v6molecule in corre-lation with p53and Ki -67presence in primary and metastatic lesion of ovarian carcin oma to define their role in metastases of ovarian carcinoma.The expression of type IV collagen,CD44v6,p53,and Ki -67was evaluated on frozen tissue sections from primary ovarian tumors(malignant n =37,benign n =16),metastatic lesions(n =29)and ascitic fluid cells(n =28).Protein ex-pression of all studied biomarkersw as evaluated in a subset of specimens using immunohistochem istry(IHC).Type IV collagen expression in the primary o varian carcinoma was positively correlated with International Federation ofGyne-cology andObstetrics(FIGO)-stage and tumor grade.Significant difference was observe d for type IV collagen immunoreactivity in carcinoma cell s in effusions when compared to corresponding primary t umors(P<0.001)and metastatic lesions(P<0.001).Likewise downreg-ulation of type IV collagen expression was seen in pri-mary ovarian carcinomas(P =0.01),ascitic fluid cells(P<0.001),and metastases(P =0.003)when com-pared to benign ovarian neoplasms.CD44v6expression was detected in a comparable percentage of primary carcinomas(51%)and metastatic lesions(52%).In cells isolated from ascitic fluid,CD44v6immunopositivity was observed in 43%of cases.A comparative analysis of primary and metastatic tumors and carcinoma cells in effusion did not reveal differences in expression of CD44v6.Positivity of CD44v6was found in 2/16(12%)of benign ovarian neoplasms.There were no significan t differences between CD44v6expression in benign neoplasms compared to pri-mary malignant tumors and metastase s(P>0.05).CD44v6expression in primary ovaria n carcinomas was as-sociated with higher tumor grade(P =0.01)and histo-logical type of tumors(P =0.01).An inverse relation-ship of type IV collagen expression w ith p53and CD44v6positivity in benign and malignant ovarian tumors was found(P>0.01).Type IV collagen expression was inversely correlated with p53status(P =0.03)in metastatic le-sions.A slight trend toward an inverse correlation between Ki -67and type IV collagen expressio n was observed inboth benign and malignant ovarian tu mors and metastases.Our data suggest that observed inverse correlation of type IV collagen expression with p53,CD44v6,and slight with Ki -67positivity in primary benign a nd malignant tumors indicates that these molecules may c ooperate in the inva-sion and progression of ovarian carc inomas. Loss of basement membrane (BM) components, such as type IV collagen has been demonstrated in ovarian cancer, but the associations with other mole cules like CD44v6, involved in metastatic process of ovarian carcinoma, have not been fully analyzed. This study i examined ex-pression of type IV collagen, CD44v6molecule in corre-lation with p53 and Ki-67 presence in primary and metastatic lesion of ovarian carcin oma to define their role in metastases of ovarian carcinoma. The expression of type IV collagen, CD44v6, p53, and Ki -67 is evaluated on frozen tissue sections from primary ovarian tumors (malignant n = 37, benign n = 16), metastatic lesions (n ​​= 29) and ascitic fluid cells (n = 28) .Protein ex- pression of all studied biomarkersw as evaluated in a subset of specimens using immunohistochemistry (IHC). Type IV collagen expression in the primary o varian carcinoma was positively correlated with International Federation of Gynecology and Obstetrics (FIGO) -stage and tumor grade. observe d for type IV collagen immunoreactivity in carcinoma cell s in effusions when compared to corresponding primary tumors (P <0.001) and metastatic lesions (P <0.001) .Likewise downreg-ulation of type IV collagen expression was seen in pri-mary ovarian carcinomas (P = 0.01), ascitic fluid cells (P <0.001), and metastases (P = 0.003) when com- pared to benign ovarian neoplasms. CD44v6 expression was detected in a comparable percentage of primary carcinomas (51%) and metastatic lesions 52%). In cells isolated from ascitic fluid, CD44v6 immunopositivity was observed in 43% of cases. A comparative analysis of primary and metastatic tumors and carcinoma cells in effusion did not reveal differences in expression of CD44v6.Positivity of CD44v6 was found in 2/16 (12%) of benign ovarian neoplasms.There were no significan t differences between CD44v6expression in benign neoplasms compared to pri-mary malignant tumors and metastase s (P> 0.05) .CD44v6expression in primary ovaria n carcinomas was as-sociated with higher tAn inverse relationship-ship of type IV collagen expression w ith p53 and CD44v6 positive in benign and malignant ovarian tumors was found (P> 0.01). Type IV Collagen expression was inversely correlated with p53status (P = 0.03) in metastatic le-sions. A slight trend toward an inverse correlation between Ki-67 and type IV collagen expressio n was observed in benign and malignant ovarian tu mors and metastases. Our data suggest that observed inverse correlation of type IV collagen expression with p53, CD44v6, and slight with Ki-67positive in primary benign a nd malignant tumors that those molecules may c ooperate in the inva-sion and progression of ovarian carc inomas.