Abstract: Aldehyde dehydrogenase 1 (ALDH-1) is a marker of stem cells in a variety of diseases, but its role in individuals with chronic inflammatory periapical lesions remains unknown. The aim of this study was to investigate the presence of cells with a stem cell profile based on the immunoexpression of ALDH-1 in periapical granulomas (PGs) and radicular cysts (RCs). A total of 51 cases of periapical lesions (25 PGs and 26 RCs) were subjected to immunohistochemical study. The anti-ALDH-1 antibody was applied using the immunoperoxidase technique. An immunoexpression score (intensity vs. percentage of cells) was used, with the cases being classified as low expression (score: 0 to 4) and high expression (score: 6 to 9). The Chi-square test was used with a 5% level of significance. Immunoexpression of ALDH-1 was detected in all cases of PGs and RCs. In PG cases, the expression was diffuse in connective tissue cells, with most cases exhibiting high expression (n = 18; 69.2%), while in RC cases the expression revealed focal distribution in cells of the capsule and epithelial cells of the cystic lining, with most cases classified as low expression (n = 18; 72%). Significant differences in the expression scores of ALDH-1 were observed in PGs (p = 0.003). The variable expression of ALDH-1 suggests the presence of cells with stem cell profiles in PGs and RCs. These findings suggest that periapical tissues infiltrated by chronic inflammation can recruit important cells for the repair or evolution of periapical lesions.

Abstract Matrix degradation is an important event in the progression, invasion and metastasis of malignant head and neck lesions. Imbalances, mutations and polymorphisms of MMPs and their inhibitors are observed in several cancer subtypes. The aim of this study was to evaluate the association of the MMP-7 gene promoter (181 A/G) and MMP-9 (-1562 C/T) polymorphisms in oral tongue squamous cell carcinoma (OTSCC). MMP-7 (rs11568818) and MMP-9 (rs3918242) single-nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in 71 cases of OTSCC. Normal tissue specimens were obtained from 60 healthy volunteers to serve as the control. The MMP-7 G allele and MMP-9 T allele were more frequent in the OTSCC group than the control group, but only when these two SNPs were taken together was a significant association found with the nodal metastasis of OTSCC (p < 0.001). Based on our results, SNPs in the promoter region of MMP-7 and MMP-9 appear to be associated with greater risk of developing OTSCC, and with a higher propensity to form metastatic tumors. In this respect, molecular studies investigating polymorphisms may be useful in predicting tumor behavior.

Abstract Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) act in the proteolysis of basement membrane and extracellular matrix structures, facilitating tumor invasion. The purpose of this study was to evaluate the relationship between these proteins and clinicopathological parameters in squamous cell carcinoma of the oral tongue (SCCOT). Sixty cases of SCCOT were submitted to immunohistochemistry and analyzed semiquantitatively at the invasion front and in the tumor core. The results were associated with lymph node metastasis, clinical stage, locoregional recurrence, clinical outcome and histological grade of malignancy. A higher expression of uPA was observed in cases of tumors of high-grade versus low-grade malignancy (p = 0.010). Moreover, the cases with the worst pattern of invasion presented an overexpression of uPA (p = 0.011). The presence of locoregional recurrence was associated with uPAR (p = 0.039), and the expression of both biomarkers was much higher at the invasion front than in the tumor core (p < 0.001). The results suggest uPA and uPAR are involved in the progression and aggressiveness of SCCOT, mainly at the tumor-host interface.

Abstract The objective of this study was to evaluate the expression of matrix metalloproteinase 9 (MMP-9) and transforming growth factor beta (TGF-β1) in periapical lesion samples correlated with the intensity of the inflammatory infiltrate and thickness of the epithelial lining. Forty-five cases of periapical lesions (23 periapical granulomas and 22 radicular cysts) were subjected to morphological and immunohistochemical analyses using anti-MMP-9 and anti-TGF-β1 antibodies. The data were analyzed using the following tests: non-parametric Mann-Whitney, chi-square, Fisher’s exact test and Spearman’s correlation test (P<0.05). Analysis of inflammatory infiltrate revealed that 78% of periapical granulomas presented infiltrate grade III, in contrast with 32% of radicular cysts (P<0.001). Morphological evaluation of the epithelial thickness in radicular cysts revealed the presence of atrophic epithelium in 86% of the cysts. The immunostaining of MMP-9 was score 2 in 67% of the granulomas and 77% of the cysts. Both lesions were predominantly score 1 for TGF-β1. Significant differences were confirmed between the expression scores of TGF-β1 and MMP-9 in periapical granulomas (p = 0.004) and in radicular cysts (p < 0.001). Expression of TGF-β1 was different for periapical granulomas and radicular cysts. This immunoregulatory cytokine seems more representative in asymptomatic lesions. The extracellular matrix remodeling process dependent on MMP-9 seems to be similar for both periapical granulomas and radicular cysts. TGF-β1 and MMP-9 may play an important role in the maintenance of periapical lesions.