title: Higher expression of human kallikrein 10 in breast cancer tissue predicts tamoxifen resistance.
abstract: The human tissue kallikreins are secreted serine proteases, encoded by a group of homologous genes clustered in tandem on chromosome 19q13.3-4. Human kallikrein 6 and human kallikrein 10 are two new members of this family. Recently, we developed highly sensitive and specific immunofluorometric assays for human kallikrein 6 and human kallikrein 10, which allow for their quantification in tissue extracts and biological fluids. Both human kallikrein 6 and human kallikrein 10 are found to be down-regulated in breast cancer cell lines, suggesting that they may be involved in breast cancer pathogenesis and progression. In this study, we investigated the potential value of human kallikrein 6 and human kallikrein 10 as prognostic and predictive factors in breast cancer. We quantified human kallikrein 6 and human kallikrein 10 protein levels in 749 breast tumour cytosolic extracts and correlated this data with various clinicopathological variables and patient outcomes. Human kallikrein 6 and human kallikrein 10 are positively correlated with each other. Higher human kallikrein 6 and human kallikrein 10 protein levels are associated with younger age, pre-menopausal, status and tumours which are negative for oestrogen and progesterone receptors. No correlation was found between human kallikrein 6 and human kallikrein 10 levels and tumour size, grade, and nodal status. Survival analysis showed that neither human kallikrein 6 nor human kallikrein 10 are related to the rate of relapse-free and overall survival. In the analysis with respect to response to tamoxifen therapy, although human kallikrein 6 levels were not associated with tamoxifen responsiveness, higher levels of human kallikrein 10 were significantly associated with a poor response rate. This association remained significant in the multivariate analysis. Furthermore, higher human kallikrein 10 levels were significantly related with a short progression-free and post-relapse overall survival after start of tamoxifen treatment for advanced disease. Taken together, our results suggest that although human kallikrein 6 and human kallikrein 10 are not prognostic markers for breast cancer, human kallikrein 10 is an independent predictive marker for response of tamoxifen therapy.
authors.affiliation: Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada.
authors.forename: L-Y
authors.initials: LY
authors.lastname: Luo
authors.forename: E P
authors.initials: EP
authors.lastname: Diamandis
authors.forename: M P
authors.initials: MP
authors.lastname: Look
authors.forename: A P
authors.initials: AP
authors.lastname: Soosaipillai
authors.forename: J A
authors.initials: JA
authors.lastname: Foekens
mesh_terms: D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000401:mortality; D002874:Chromosome Mapping; D002888:Chromosomes, Human, Pair 19; D003600:Cytosol / Q000201:enzymology; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D007610:Kallikreins / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D015996:Survival Rate; D013629:Tamoxifen / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen; C100936:KLK10 protein, human; C103551:KLK6 protein, human; D007610:Kallikreins