Análise comparativa da imunoexpressão das proteínas hmlh1 e hmsh2 em carcinomas epidermóides de lábio inferior e queilites actínicas com graus variados de displasia
Lip squamous cell carcinoma (SCC) may develop from a premalignant condition, actinic cheilitis (AC) in 95% of the cases. Both premalignant and neoplastic lip diseases are caused mainly by chronic exposure to the ultraviolet component of solar radiation, especially UVB. This exposure causes disruptio...
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| Formato: | Dissertação |
| Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/17116 |
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| Resumo: | Lip squamous cell carcinoma (SCC) may develop from a premalignant condition,
actinic cheilitis (AC) in 95% of the cases. Both premalignant and neoplastic lip diseases are
caused mainly by chronic exposure to the ultraviolet component of solar radiation, especially
UVB. This exposure causes disruption of the cell cycle and damage to DNA repair systems,
like mismatch repair, altering proteins repair as hMLH1 and hMSH2. This research aimed to
investigate the immunohistochemical expression of hMLH1 and hMSH2 proteins in lower lip
SCCs and ACs, providing additional information about carcinogenesis of the lower lip. The
sample consisted 40 cases of ACs and 40 cases of lower lip SCCs. Histological sections of 3
μm were submitted to immunoperoxidase method, for immunohistochemical analysis of
lesions were counted in 1000 cells (positive and negative), data were evaluated both in
absolute numbers and percentage of immunostained cells, the latter by assigning scores.
Associations of the variables and comparative analysis of biomarker expression were
performed by Fisher s exact and Pearson s chi-square, "t" student, one-way ANOVA, Mann-
Whitney e Kruskal-Wallis tests. The level of significance was 5%. It was found that, in lower
lip SCC, the mean of the proteins was higher in female patients (hMLH1= 369,80 + 223,98;
hMHS2 = 534,80 + 343,62), less than 50 years old (hMLH1 = 285,50 + 190,65; hMHS2 =
540,00 + 274,79) and classified as low-grade malignancy (hMLH1 = 264,59 + 179,21;
hMHS2 = 519,32 + 302,58), in these data only to sex, for hMLH1 protein, was statistically
significant (p=0.034). Comparing the different lesions, we observed that for both hMLH1 and
hMSH2 protein, the average of positive epithelial cells decreased as the lesion was graded at
later stages. The ACs classified without dysplasia or mild dysplasia had the highest average of
immunostained cells (hMLH1 = 721.23 + 88.116; hMHS2 = 781.50 + 156.93). The ACs
classified as moderate or severe dysplasia had intermediate values (hMLH1 = 532,86 +
197,72; hMHS2 = 611,14 + 172,48) and SSCs of the lower lip had the lowest averages
(hMLH1 = 255,03 + 199,47; hMHS2 = 518,38 + 265,68). There was a statistically significant
difference between groups (p<0.001). In conclusion, our data support the hypothesis that
changes in immunoexpression of these proteins is related to the process of carcinogenesis of
the lower lip |
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