Etapas da progressão do carcinoma espinocelular cutâneo: estudo imuno-histoquímico das proteínas p53 e Ki-67 e de marcadores endoteliais / Steps of progression in cutaneous squamous cell carcinoma: an immunohistochemical study of p53 and Ki67 proteins and endothelial markers

As etapas cruciais da carcinogênese cutânea incluem disfunção da proteína supressora tumoral p53 e angiogênese. A contribuição de tais eventos, individual e sinergicamente, ainda não está bem estabelecida na cascata de fenômenos que resultam no carcinoma espinocelular cutâneo. Objetivou-se avaliar a expressão imuno-histoquímica da p53, o índice proliferativo e a angiogênese nos estádios evolutivos do carcinoma espinocelular cutâneo, e investigar a relação da expressão da p53 com as demais variáveis. Foram estimadas as porcentagens de células imunomarcadas para p53 e Ki-67 em três grupos de cânceres: 30 queratoses solares, 30 carcinomas espinocelulares superficialmente invasores e 30 carcinomas espinocelulares invasores. O método Chalkley foi utilizado para quantificar a área microvascular, empregando-se marcador de neoangiogênese (CD105) e pan-endotelial (CD34) em cada grupo. A área microvascular em amostras marcadas pelo CD105 aumentou, significantemente, com a progressão do carcinoma espinocelular cutâneo. O mesmo não ocorreu com o uso do CD34. Contudo, nos três grupos (queratose solar, carcinoma espinocelular superficialmente invasor e invasor) encontrou-se aumento significante da área microvascular, com ambos os marcadores (CD34 e CD105), em comparação à respectiva pele adjacente. Não houve diferença significante na taxa de células positivas para p53 e Ki-67 entre os grupos. Encontrou-se correlação positiva e significante entre a área microvascular marcada pelo CD105 e o índice de marcação para a p53 no carcinoma espinocelular superficialmente invasor, bem como entre o índice de marcação para p53 e para o Ki-67 no carcinoma espinocelular invasor. A conversão angiogênica é um evento precoce no carcinoma espinocelular cutâneo, e a neovascularização é paralela à progressão do tumor. O uso do CD105 permite avaliar a atividade angiogênica no tumores escamosos. A angiogênese no estádio inicial da invasão e a atividade proliferativa na fase francamente invasora estão associadas com a expressão imuno-histoquímica da proteína p53. A perda da função supressora tumoral da p53, em etapas progressivas, atua diretamente na carcinogênese cutânea. (AU)

Multistep skin carcinogenesis crucially involves loss of function of p53 tumor suppressor protein and angiogenesis. The contribution of such events, individually and synergically, is not well established in the cascade of phenomena that results in cutaneous squamous cell carcinoma. We aimed to evaluate the immunohistochemical expression of p53, the proliferative index and angiogenesis in spectral stages of cutaneous squamous cell carcinoma, and investigate the relationship between p53 expression with the other variables. We estimated the percentages of immunostained cells for p53 and Ki-67 (proliferation marker) in three groups of cancer: 30 solar keratoses, 30 superficially invasive squamous cell carcinomas and 30 invasive squamous cell carcinomas. The Chalkley method was used to quantify the microvascular area by neoangiogenesis (CD105) and panendothelial (CD34) immunomarker in each group. The microvascular area in CD105-stained specimens significantly increased with cutaneous squamous cell carcinoma progression. However, no differences between groups were found in CD34 sections. Solar keratosis, superficially invasive squamous cell carcinoma and invasive squamous cell carcinoma samples showed significant increases in microvascular area for both CD34- and CD105-stained specimens compared with the respective adjacent skin. There was no significant difference for the rate of p53- and Ki-67-positive cells between the groups. Significant positive correlation was found between the CD105 microvascular area and the rate of p53 positive cells in superficially invasive squamous cell carcinoma as well as between the rate of p53- and Ki-67-positive cells in invasive squamous cell carcinoma. The angiogenic switch is an early event in cutaneous squamous cell carcinoma, and the rate of neovascularization is parallel to tumor progression. In contrast to panendothelial markers, CD105 use allows evaluating angiogenic activity in squamous tumors. Neovascularization in the initial stage of invasion and proliferative activity in the frankly invasive stage were both associated with p53 immunoexpression. Loss of p53 tumor suppressor function through progressive steps is directly involved in skin carcinogenesis.(AU)

Angiogenesis in the progression of cutaneous squamous cell carcinoma: an immunohistochemical study of endothelial markers

OBJECTIVE: To demonstrate the role of angiogenesis in the progression of cutaneous squamous cell carcinoma. INTRODUCTION: Angiogenesis is a pivotal phenomenon in carcinogenesis. Its time course in cutaneous squamous cell carcinoma has not yet been fully established. METHODS: We studied the vascular bed in 29 solar keratoses, 30 superficially invasive squamous cell carcinomas and 30 invasive squamous cell carcinomas. The Chalkley method was used to quantify the microvascular area by comparing panendothelial (CD34) with neoangiogenesis (CD105) immunohistochemical markers. The vascular bed from non-neoplastic adjacent skin was evaluated in 8 solar keratoses, 10 superficially invasive squamous cell carcinomas and 10 invasive squamous cell carcinomas. RESULTS: The microvascular area in CD105-stained specimens significantly increased in parallel with cutaneous squamous cell carcinoma progression. However, no differences between groups were found in CD34 sections. Solar keratosis, superficially invasive squamous cell carcinoma and invasive squamous cell carcinoma samples showed significant increases in microvascular area for both CD34- and CD105-stained specimens compared with the respective adjacent skin. DISCUSSION: The angiogenic switch occurs early in the development of cutaneous squamous cell carcinoma, and the rate of neovascularization is parallel to tumor progression. In contrast to panendothelial markers, CD105 use allows a dynamic evaluation of tumor angiogenesis. CONCLUSION: This study demonstrated the dependence of skin carcinogenesis on angiogenesis.