Activation of this enzyme doesn’t require calcium ions and calmodulin, and
leads to production of high concentration of NO, which may be sustained for
a long period. Different expression of NOS has been described in many
human and experimental tumors, such tumors of the human reproductive
tract, breast, central nervous system, and non-Hodgkin lymphomas. We
retrospectively analyzed immunohistochemistry expression “in situ” of nitric
oxide synthase isoforms in 117 patients at diagnostic with use the tissue
microarray technique. These patients are registered in Department of
Pathology, Centro de Tratamento e Pesquisa Hospital do Câncer A C
Camargo, São Paulo, Brazil, from 1980 to 2001. The NOS-1 isoform (78,6%)
was expressed more than NOS-3 (71,8%) and than NOS-2 (61,6%). The
NOS-1 and NOS-3 staining were localized in the cytoplasm and nuclei of
neoplastic cells, while NOS-2 was present only in the cytoplasm of the tumor
cell. The expressions of NOS-1 (p=0,009) and NOS-3 (p=0,003) was
positively correlated with serum β2-microglobulin > 3,5mg/dl. There was a
significant positive correlation between NOS-2 expression and cytological
atipias (p= 0,016), serum albumin < 3,5g/dl (p=0,045), and secretion of light
chain immunoglobulin (p=0,046). Any NOS expressions were statistically
significant to predict risk in these patients. Serum hemoglobin level less than
10,0g/dl (p<0,001), serum albumin < 3,5g/dl (p=0,007) and serum level
creatinine > 1,4mg/dl (p=0,001), were significant to provide survival when to
apply somatory score (p< 0,001). The tissue microarray technique offered
faster and cheaper molecular profile using immunohistochemistry in large
numbers of tissue samples. Plasma cells neoplasias are able to express
immunohistochemically NOS isoforms. Constitutives NOS are more
expression than inducible in this study; datas doesn’t compatible with
previous reports in the literature. It is maybe can be proved the involvement
of NO in inhibit apoptosis and promote angiogenesis. Nevertheless, there is
correlation statistically significant with expression of constitutive NOS and
serum β2-microglobulina, the most important variable predicting survival in
multiple myeloma. In this study, anemia, low rates of albumin and high serum
creatinine identifying very poor risk patients.