Elevated Soluble Galectin-3 as a Marker of Chemotherapy Efficacy in Breast Cancer Patients: A Prospective Study

Figure 1

Stromal Galectin-3 (Gal-3) levels decrease with increasing tumor grade in breast cancer patients: (a) Gal-3 localization and expression levels were examined through immunohistochemistry (IHC) of paraffin-embedded tissue sections from all study patients () at the time of diagnosis prior to any treatment. Normal breast tissue has undetectable levels of Gal-3 while low-grade tumors show high Gal-3 expression in stroma and extracellular spaces. These levels decline with increasing grade. Representative images from each category are shown at 400x final magnification. (b) Average stromal Gal-3 expression levels are shown in grades I-IV breast carcinoma tissues from our study patients (). Gal-3 levels in stroma were quantified as 0-4 based on expression intensity. Average of three separate blinded observations is shown. Expression levels rose between grades I and II () and then dropped significantly with increasing grade ( grades II vs. III; grades III vs. IV). (c) Gal-3 concentration in plasma from study patients was quantified through ELISA in the various study groups. The average levels remained unchanged prior to therapy compared to nontumoral controls. Each plasma sample was quantified in triplicate ( nontumoral controls; adjuvant; neoadjuvant patients). (d) Average Gal-3 plasma levels in each category are negatively correlated to tumor grade. Plasma levels of Gal-3 were quantified by ELISA. Gal-3 levels were found to be significantly elevated in plasma from low grade breast cancer patients (stages I and II ()) prior to any treatment compared to nontumoral controls (). The Gal-3 levels dropped sharply in grade IV and metastatic cancers (; ). Low levels of Gal-3 (; range: 3.0-34.0 ng/ml) were observed in healthy adult women () plasma. 21.0 ng/ml (95^th percentile) was considered to be the top limit of normal levels in our analysis. Error bars show ±SEM.

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