BACKGROUND:
Signal transducer and activator of transcription 3 (STAT3) is not only a key signaling molecule in the
regulation of
growth but is also involved in malignant transformation. We investigated the prognostic significance of STAT3 expression in 94 non-
elderly adult patients (
aged 38 to 65 yr) with newly diagnosed
multiple myeloma (MM).
METHODS:
Tumor cell-specific
phosphotyrosine-STAT3 (PY-STAT3) expression at the
time of
diagnosis was evaluated with dual immunohistochemical (IHC)
staining for PY-STAT3 and CD138.
RESULTS:
PY-STAT3 positivity was detected in 10
patients (10.6%), including three
who showed strong expression. PY-STAT3-positive
patients had higher
serum C-reactive protein and
calcium levels at
diagnosis than did PY-STAT3-negative
patients. PY-STAT3 positivity had predictive value for poor
progression-free survival (PFS; P=0.001) and overall
survival (OS; P=0.003). Among the 60
patients who received frontline autologous
stem cell transplantation, PY-STAT3-positive
patients had poorer PFS than did PY-STAT3-negative
patients (4.2 vs. 19.2 mo, respectively; P=0.013).
Multivariate analysis identified PY-STAT3 expression as an independent
prognostic factor for PFS (
relative risk [RR]=2.706, P=0.014) and OS (RR=3.091, P=0.044).
CONCLUSION:
These data show that PY-STAT3 positivity, as determined using dual IHC, is a marker of poor
prognosis in non-
elderly adult patients with MM.