Expression of phosphorylated and non-phosphorylated neurofilament subunits and cytokeratins in neuroendocrine lung tumors.
In this study antibodies specific for different intermediate-sized proteins (cytokeratins and neurofilaments) have been tested on a series of neuroendocrine (NE) lung tumors in order to evaluate their diagnostic validity. In particular we used a panel of polyclonal anti-neurofilament 200-kilodalton subunits whose reactivity against phospho-dependent epitopes was known. At least one NF subunit was constantly present and in all cases coexpression of cytokeratins and neurofilaments was confirmed. However, in cases of carcinoid tumor (CT) the results were homogeneous, while the cases of small cell lung carcinoma (SCLC) showed a much wider range of immunostaining. Our investigation confirms the hypothesis that the phosphorylation state is a significant determinant of immunohistochemical properties of neurofilaments. This might explain the large number of negative results obtained in previous investigations on NE tumors. The phosphorylation of neurofilaments may also be considered an indication of the degree of differentiation of the tumor.
Leoncini
P
P
Sclavo Research Centre, Siena, Italy.
Bellizzi de Marco
E
E
Bugnoli
M
M
Mencarelli
C
C
Vindigni
C
C
Cintorino
M
M
D014408:Biomarkers, Tumor / Q000032:analysis; D002277:Carcinoma / Q000032:analysis / Q000378:metabolism* / Q000473:pathology; D018288:Carcinoma, Small Cell / Q000032:analysis / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis / Q000378:metabolism*; D007633:Keratins / Q000032:analysis / Q000378:metabolism*; D008175:Lung Neoplasms / Q000032:analysis / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation
D014408:Biomarkers, Tumor; D007381:Intermediate Filament Proteins; D007633:Keratins