Avaliação da progressão tumoral em carcinoma de células escamosas de lábio inferior

Abstract

Background: Squamous cell carcinoma of the lower lip (SCCLL) is recognize as the oral malignancy of larger incidence, especially in populations with high exposure to solar radiation. Objective: This study aimed to analyze the immunoexpression of EGFr, Ki-67 and p27 proteins in SCCLL evaluating regions that represent distinct stages of lesion development, in order to verify the use of these proteins as markers of tumor progression. Method: We analyzed a sample of 32 SCCLL and 32 cases of normal oral epithelium represented by phenomena of extravasation of mucus as a comparative group. All cases of SCCLL were analyzed based on their clinical characteristics such as gender, age, race, occupational activity, exposure to solar radiation and clinical staging (TNM), and histologically for the presence of cellular atypia in the epithelium adjacent to the tumor and to the front invasion. In the adjacent epithelium was used the classification to degrees of epithelial dysplasia as mild, moderate and severe by Gale et al., (2005) and adapted of Warnakulasuriya et al., (2008), and to the invasive front was used the malignancy classification suggested by Bryne (1998) and adapted by Silveira et al. (2010) classifying the cases into high and low degrees of malignancy. Additionally the entire tumor area was classified according to the histological gradation by Cardesa et al.,(2005) in welldifferentiated, moderately differentiated and poorly differentiated tumors. To the analysis of the immunostaining of EGFr protein was considered the mark to the cytoplasmic membrane and its expression pattern was classified as absent, weak, moderate and intense (DINIZFREITAS et al., 2007). For p27 and Ki-67 proteins were counted the positive and negative cells in a set of 500 cells to obtain the index of positivity (ROCK, SOUZA, PINTO, 2007). Results: The results revealed that males (n = 23/71.9%), 61 years old or older (n = 19/59.3%) and Caucasians (n = 22/68.8%) were more frequent and farmers (n = 25/78.1%), exposed to solar radiation (n = 26/81.2%) and lesions clinically in the early stages I and II (28/87.5%) were the most frequent findings. The mild dysplasia (n = 18/56, 3%), the histological grading in front of low grade (n = 19/59.4%) and the well differentiated cases (n = 16/50.0%) predominated. The front grading and grading across tumor extension showed a statistical association (p = 0.004). The difference in expression between normal epithelium and SCCLL was not significant for KI-67, while the expression of p27 was significant in the adjacent epithelium (p=0.025), tumor chorion (p<0.001) and the front of invasion (p<0.001), and the staining of EGFr protein was significant only in front of invasion (p = 0.047). The analysis of the tumoral areas showed no significant difference in scores of EGFr and Ki-67 proteins,while, the p27 protein showed a progressive decrease of expression as it was performed the analysis of the adjacent epithelium to the front of invasion (p<0.001). Conclusion: The protein EGFr and p27 are involved in tumor progression, is related to the process of cellular proliferation or other signaling pathways. These findings suggest the use of proteins as p27 and EGFr markers of tumor progression in CCELI, and the protein Ki-67 as a marker of cell proliferation.