Study on collagen parameters in vulvar cancer and preneoplastic lesions by Second Harmonic Generation microscopy.

The extracellular matrix plays an important role in cellular balance, and collagen fibers are its most important component. Over the last few years, second harmonic generation (SHG) microscopy has been used for the analysis of collagen fibers in several types of gynaecological cancers, such as breast and ovarian cancer. The value of collagen parameters obtained with this technique to gain insights on the physiopathology and on the prognostic evaluation of cancer has been advocated. Herein, we have characterized the collagen fibers in squamous cell carcinoma (VSCC) and preneoplastic lesions using the SHG microscopy. Collagen parameters, quantity, organization, and uniformity, of VSCC, adjacent skin of VSCC or preneoplastic lesions were compared with values obtained in normal tissue of healthy control. There was an evident decrease in the values of collagen fiber parameters in the VSCC. Increased quantity and uniformity of tumor associated collagen fibers were associated with the presence of lymph node metastases, which suggest a prognostic value of such parameters in the evaluation of vulvar cancer.

Estudo da expressão de colágeno no câncer vulvar e lesões pré-neoplásicas pelo método de Second Harmonic Generation / Quantitative study of collagen in vulvar carcinoma and intraepithelial vulvar neoplasia using the Second Harmonic Generation microscopy

Introdução: A matriz extracelular (MEC) desempenha um papel importante na função celular, sendo que seu componente mais importante são as fibras de colágeno (COL). Nos últimos anos, a Microscopia de Geração Segundo Harmônico (em inglês, second harmonic generation microscopy; SHG) tem sido utilizada para a análise de COL em vários tipos de cânceres ginecológicos, como o da mama e ovário. Desta forma, tem-se enfatizado o valor da quantificação do colágeno por este método como meio de aprofundar o conhecimento da fisiopatologia e do prognóstico na avaliação destas neoplasias. Objetivo: No presente estudo caracterizamos as fibras de COL utilizando-se a microscopia de SHG objetivando avaliar diferenças entre carcinoma de células escamosas e lesões pré-neoplásicas da vulva, bem como verificar se há relação entre características dessas fibras com parâmetros clinicopatológicos associados a prognóstico. Método: Trata-se de um estudo de coorte horizontal e retrospectivo. Foram incluídos 52 pacientes, entre os anos de 2000 a 2010, sendo 40 com Carcinoma de Células Escamosas (CCE) Vulvar; 12 pacientes com Neoplasia Intraepitelial Vulvar (NIV); e, para o controle de comparação interna, foram considerados tecidos distantes ao tumor sem presença de lesão tumoral e/ou NIV. Para análises laboratoriais, foi selecionado um espécime representativo do processo patológico para revisão diagnóstica; e, posteriormente, submetido ao estudo do COL usando a microscopia de SHG. Os tecidos adjacentes normais e intratumorais foram selecionados em secções, para a avaliação do COL, e corados em Hematoxilina/Eosina (H&E) e analisados por microscopia confocal. Parâmetros relacionados ao colágeno, como quantidade, organização e uniformidade, em áreas de lesões neoplásicas e pré-neoplásicas da vulva, foram comparados com áreas distantes de aspecto normal das mesmas pacientes. Resultado/conclusão: Foi observado um evidente decréscimo nos valores dos parâmetros do COL no estroma associado às lesões pré-neoplásicas e neoplásicas da vulva. Além disto, aumentos na quantidade e uniformidade das fibras do colágeno tumorais se associaram à presença de metástases linfonodais, um reconhecido parâmetro de pior prognóstico no carcinoma de vulva

Background: The extracellular matrix (ECM) plays an important role in cellular function, being collagen fibers its most important component. Over the last few years, second harmonic generation (SHG) microscopy has been used for the analysis of collagen fibers in several types of cancers, including breast and ovarian cancer. The value of collagen parameters obtained using this technique has been advocated to gain insights on the physiopathology and on the prognostic evaluation of cancer. Objective: Herein, we have characterized collagen fibers using the SHG microscopy, to evaluate differences between vulvar cancer and preneoplastic lesions, and to find possible associations between characteristics of collagen fibers with clinicopathological parameters related to prognosis. Methods: This is a retrospective and horizontal cohort study. Were included 52 patients, between the years 2000 to 2010, 40 of whom with Vulva Squamous Cell Carcinoma (VSCC); 12 patients with Vulvar Intraepithelial Neoplasia (VIN); and, for the control of internal comparison, tissues distant to the tumor without tumor lesion and / or VIN were considered. For laboratory analysis, a specimen representative of the pathological process was selected for diagnostic review and subsequently subjected to the study of collagen using SHG microscopy. The normal and intratumoral adjacent tissues were selected in sections, for collagen evaluation, and stained in Hematoxylin/Eosin (H&E) and analyzed by confocal microscopy. Collagen parameters, quantity, organization, and uniformity, of stroma adjacent to neoplastic or preneoplastic lesions were compared with values obtained in normal appearing tissue distant from those lesions from the same patients. Results/Conclusion: There was an evident decrease in the values of collagen fiber parameters in the stroma associated to tumors. Increased quantity and uniformity of tumor associated collagen fibers were associated with the presence of lymph node metastases, which suggest a prognostic value of such parameters in the evaluation of vulvar cancer