Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Anatomy and Cell Biology

Collaborative Specialization

Developmental Biology


Postovit, Lynne-Marie

2nd Supervisor

Lajoie, Gilles A



Cancers exist within complex microenvironments formed by heterogeneous cell types. This diversity creates significant challenges for detection, diagnosis and treatment. Mass spectrometry-based proteomics is a powerful approach capable of characterizing complex biological systems which are characteristic of cancer biology. In this thesis, proteomics was utilized to answer several questions related to ovarian cancer diagnosis and detection, and the effects of NODAL, an embryonic morphogen, on the breast cancer secretome and stromal cell recruitment. First, I compared multiple sample preparation techniques and found high-pH/low-pH fractionation to yield the greatest proteome coverage over commonly used approaches. Second, I compared the proteomes from two ovarian cancer subtypes (high-grade serous and endometrioid) for which histological discrimination remains difficult in a proportion of cases. I documented several unknown proteins, including KIAA1324, which were validated and confirmed to improve the differential diagnosis of endometrial ovarian cancer. Third, I extensively characterized extracellular vesicle proteomes from biological fluids (conditioned media, plasma and ascites) to catalogue potential biomarkers associated with malignant ovarian cancer. I detected many factors associated with advanced stage, high-grade serous ovarian cancer including CFHR4, MUC1, APCS and PZP that may be useful for early detection. Last, I characterized the global effects of the Transforming Growth Factor-β superfamily member NODAL on the breast cancer secretome and stromal cell recruitment in vitro. I found a previously unknown role for NODAL in modulating pro-inflammatory factors, including CXCL1 and IL6 that were correlated with multipotent stromal cell recruitment. In summary, this work represents a significant contribution to the histological assessment and detection of ovarian cancer and our understanding of the malignant properties of NODAL within the breast cancer microenvironment.