Expression of retinoblastoma gene product in respiratory epithelium and sinonasal neoplasms: relationship with p16 and cyclin D1 expression.

Transition from G1 to S phase of the cell cycle is mediated by interactions between the Retinoblastoma gene product (pRb), p16, and cyclin D1. To determine the expression of these proteins in the sinonasal mucosa immunohistochemistry was carried out on archived tissue sections from 46 patients (37 men, 9 women, age range 17 to 82 years, median 55 years). Nuclear immunostaining for these proteins was assessed and the expression rates (percentages of immunoreactive nuclei) in normal respiratory epithelium, inverted sinonasal papillomas, cylindrical (oncocytic) sinonasal papillomas, and squamous cell carcinomas were compared.

Differentiation-related p53 protein expression in nondysplastic sinonasal inverted papillomas.

To clarify p53 protein expression in nondysplastic sinonasal inverted papillomas, archived surgical specimens from 19 patients were studied using immunohistochemistry. Staining results were compared between inverted papillomas and adjacent, nonpapillomatous nasal mucosa. Further, immunoreactivity was compared between columnar (respiratory), transitional (cuboidal), and squamous epithelium in inverted papillomas.

Patterns of p21(waf1/cip1) expression in non-papillomatous nasal mucosa, endophytic sinonasal papillomas, and associated carcinomas.

Aims: To clarify p21(waf1/cip1) expression in sinonasal lesions.

Methods: Archived surgical specimens from 38 patients were investigated by means of immunohistochemistry. p21(waf1/cip1) staining was evaluated in the different layers of the epithelium.

Cytokeratin expression and epithelial differentiation in Warthin's tumour and its metaplastic (infarcted) variant.

Aims: Warthin's tumour is characterized by a bilayered columnar epithelium. Transformation into metaplastic (infarcted) Warthin's tumour includes squamous metaplasia of the epithelium along with regressive changes in the stroma. Misinterpretation of metaplastic Warthin's tumour for malignancy is a serious diagnostic pitfall.

Coexpression of cytokeratins typical for columnar and squamous differentiation in sinonasal inverted papillomas.

Cytokeratin (CK) expression was studied in 22 sinonasal inverted papillomas. Columnar (respiratory) epithelium in inverted papillomas abundantly expressed CK7, CK8, CK18, and CK19. Immunoreactivity for CK5/14 and CK17 was found in basal and parabasal/suprabasal cells.