Multimodal nonlinear optical imaging in histopathology sections reveals differences between normal and tumor stromal of human ovarian

ADUR J; PELEGATI VB; BARATTI MO; DE THOMAZ AA; BOTTCHER-LUIZ F; ANDRADE LALA; CARVALHO HF; CESAR CL

Simposio; XI Brazilian Symposium on Extracellular Matrix and VI International Symposium on Extracellular Matrix; 2011

We used a multimodal Non Linear Optics microscopy, to observe pathological conditions of ovarian tissues obtained from human samples. We show that strong Two-Photon Excited Fluorescence [TPEF], Second and Third Harmonic Generation [SHG/THG] signals can be obtained in fixed samples stained with Hematoxylin & Eosin [H&E] stored for a very long time. We then used the multimodal TPEF-SHG-THG microscopies in a stored file of H&E stained samples of human ovarian cancer to obtain complementary information about the interface epithelium/stromal, such the transformation of epithelium surface (THG) and the overall fibrillar tissue architecture (SHG). To quantitatively assess the collagen-related changes in stroma ovarian, we applied the Fourier transform analysis to the SHG images. Collagen structure and density presented several differences in fibers alignment and disposition: in normal tissue, fibers were disposed in parallel to the major axis of the epithelia, while the serous adenoma showed visible and abundant dense fibers which followed the same axis orientation of the normal ovarian tissue. On the other hand, borderline and serous adenocarcinoma presented more irregular dense fibers. This result confirms the facts that normal ovary and serous adenoma are a more organized tissue with respect to borderline and serous adenocarcinoma. To complete the analyses about collagen transformation in ovarian cancer, we quantified the collagen fiber angle relative to the epithelium. We measured previously defined tumor-associated collagen signatures (TACS). Specifically, we find the TACS-2, straightened (taut) collagen fibers stretched around the epithelium; and TACS-3, identification of radially aligned collagen fibers that facilitate local invasion. Our results showed that collagen was structurally modified (TACS-2 to TACS-3 transformation) principally in close proximity to focal areas of epithelial stratifications such as observed in serous adenocarcinoma samples. This is the first works that identify TACS-3 signatures in human ovarian tumors. This multicontrast Non Linear Optics microscopy not only can differentiate between cancerous and healthy tissue, but to distinguish the normal, benign, borderline, and malignant specimens according to their collagen disposition and compression levels within the extracellular matrix.