The expression of proliferating cell nuclear antigen (PCNA) and of nucleolar organizer regions (AgNORs) correlates with the morphological type of bone marrow plasma cells in multiple myeloma (MM).
Proliferating cell nuclear antigen (PCNA) is a DNA polymerase delta accessory protein, and is an indicator of the proliferative state of the cell. Nucleolar organizer regions (NORs) are loops of DNA that carry the ribosomal RNA (rRNA) genes and are markers of aggressiveness for certain tumors.


METHODS
This study tested the correlation between plasma cell morphology and PCNA and NOR expression in 50 multiple myeloma (MM) patients prior to therapy. 50 MM bone marrow trephine biopsies were studied using the monoclonal antibody PC-10 and the colloid silver nitrate method for identification of PCNA and AgNors, respectively.


RESULTS
PCNA positive cells ranged from 2% to 100%, higher PCNA expression was observed in patients with immature type of MM (mean 29.5%, SD = 5.5), the highest expression was seen in plasmablastic type MM (mean 60.5%, SD = 22.6). The AgNOR count was also higher in MM with plasmablasts in the bone marrow (p < 0.001). In addition, the localization of AgNOR changed according to the type of MM: in 84% of mature and intermediate MM NORs were present in the central nucleus whereas in immature and plasmablastic MM NORs were dispersed or near the membrane. Elevated PCNA expression and AgNOR counts was also seen in MM patients with hyperviscosity coma as well as in patients with renal failure.


CONCLUSIONS
PCNA expression and AgNOR count in myeloma indicates the myeloma's proliferative activity and correlates positively with the cytomorphology of plasma cells and clinical outcome.
Usnarska-Zubkiewicz
Lidia
L
Dept. of Haematology, Medical University of Wrocław.
Maryniak
Renata
R
Podolak-Dawidziak
Maria
M
Woźniak
Zdzisław
Z
Jeleń
Michał
M
Ramlau
Rodryg
R
Poreba
Małgorzata
M
Kuliczkowski
Kazimierz
K
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001809:Blood Viscosity / Q000502:physiology*; D001853:Bone Marrow / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood* / Q000503:physiopathology*; D009697:Nucleolus Organizer Region / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000097:blood*
D000911:Antibodies, Monoclonal; D018809:Proliferating Cell Nuclear Antigen