Premium
Standardization of interphase Ag‐NOR measurement by means of an automated image analysis system using lymphocytes as an internal control
Author(s) -
Derenzini Massimo,
Trerè Davide
Publication year - 1991
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/path.1711650410
Subject(s) - fixative , silver stain , staining , pathology , interphase , lymphocyte , chemistry , biology , microbiology and biotechnology , medicine , immunology
Abstract Using an automated image analysis system, we have developed a procedure for standardizing the measurement of silver‐stained proteins of the nucleolar organizer regions (NORs) in cancer cells, irrespective of the fixative employed and the time of the staining reaction. We observed that the area of Ag‐NOR proteins from the same tumour was smaller in samples fixed with formalin‐containing solutions, buffered formalin, and Bouin liquid, compared with those fixed with absolute ethanol and ‘methcarn’ solution (1·77 ± 0·26 μm 2 and 2·36 ± 0·35 μm 2 versus 3·34 ± 0·54 μm 2 and 3·72 ± 0·61 μm 2 ). Increased values of the Ag‐NOR area were also observed after lengthening the silver staining reaction. However, in both cases no difference was observed in the ratio between Ag‐NOR area of cancer cells and that of the lymphocytes infiltrating the stroma. The value of the ratio, which is called the ‘Ag‐NOR index’, was in fact very similar, for the same cancer, after employing different fixatives or staining times. The use of lymphocyte Ag‐NOR area as an internal control for the standardization of Ag‐NOR evaluation in cancer tissues was made possible by the fact that lymphocyte Ag‐NOR area is almost constant in human tumours independent of sex and age.