The importance of inducible nitric oxide synthase and nitrotyrosine as prognostic markers for oral squamous cell carcinoma.

BACKGROUND: The prognosis of human cancer depends on the deregulations of many molecular patterns. In recent years, a great interest in the intracellular signaling mechanisms related to nitric oxide (NO)-induced carcinogenesis has appeared, as one of the most preeminent prognostic markers for many types of neoplasms. In this study, we identify the levels of iNOS and nitrotyrosine in the sample of normal oral mucosa (NOM), oral leukoplakia (OL), and oral squamous cell carcinoma (OSCC). METHODS: Quantitative polymerase chain reactions (qPCRs) were utilized to detect the NOS2 levels in fresh-frozen tissue samples of NOM (n = 6), OL (n = 20), and OSCC (n = 15). Moreover, the immunohistochemical method was used to examine the levels of iNOS and nitrotyrosine in 85 cases of OSCC (39 cases without metastases and 46 with metastases), 42 cases of OL, and 16 cases of NOM. RESULTS: There are rising tendencies in the iNOS mRNA and protein levels during human oral carcinogenesis. Similar findings were obtained in the nitrotyrosine staining. Furthermore, iNOS and nitrotyrosine immunostaining are associated with several clinical-pathological features of OSCC (site, presence of metastasis, staging, recidivism, and survival). CONCLUSIONS: The NO-signaling pathway plays a vital role in the development and progression of human oral dysplastic and neoplastic diseases. Nitrotyrosine was a significant marker for the discrimination of OSCC prognosis and survival.

Orthokeratinized odontogenic cysts presenting as a periapical lesion: report of a case and literature review.

INTRODUCTION: Inflammatory cysts, granulomas, abscesses, and fibrous scars represent most periapical radiolucencies. However, other less common lesions, such as orthokeratinized odontogenic cysts (OOCs), can be found at this region, and they deserve to be discussed because the prognosis for an OOC is different from that expected for the ordinary inflammatory periapical diseases. METHODS: An interesting case of OOC associated with a nonvital tooth in a 40-year-old woman is described. After a previous clinical diagnosis of a radicular cyst, the tooth was extracted, and the lesion was enucleated and submitted to microscopy examination. RESULTS: Because of the detection of an orthokeratinized epithelium lining, a diagnosis of OOC was concluded. After 2 years of periodic follow-up, no signs of recurrence were detected. CONCLUSIONS: The presence of keratin in radicular lesions must be carefully evaluated to eliminate the diagnosis of lesions with more aggressive behavior, such as an OOC or even a keratocystic odontogenic tumor. Hence, histopathologic examination is mandatory to confirm the type of lesion and to differentiate other pathologic conditions, therefore establishing patients' prognoses precisely.