Background: Shear wave elastography (SWE) can evaluate the tissue stiffness. Previous studies showed that the elastic characteristics of breast lesions were related to the components of extracellular matrix (ECM) which was directly or indirectly regulated by transforming growth factor beta 1(TGF-β1). However, it is rarely reported whether there is a correlation between TGF-β1 and the elastic characteristics of breast lesions. The purpose of this study was to investigate the relationship between TGF-β1 with its signal transduction pathways and the elastic characteristics of breast lesions.Methods: 135 breast lesions in 130 patients were included. Before operation or biopsy, SWE was performed. Elastic characteristics such as the maximum, mean, minimum and standard deviation (SD) of elastic modulus (Emax, Emean, Emin, Esd), the elastic ratio of the lesions to the peripheral tissue (Eratio) and the "stiff rim sign" were recorded. The expression levels of TGF-β1, Smad2/3, Erk1/2, p38 MAPK, JNK2, PI3K and AKT were detected by immunohistochemistry. The elastic characteristics and the expression levels of the above-mentioned indexes of benign lesions were were analyzed.Results: Emax, Emean, Esd, Eratio, “stiff rim sign” detection rate and the expression levels of TGF- β 1, et al. of benign were lower than those of malignant lesions (P<0.0001). The expression levels of TGF- β 1, Smad2/3, Erk1/2, p38 MAPK, JNK2, PI3K and AKT were correlated with Emax, Emean, Esd, Eratio of breast lesions, the expression levels of TGF- β 1, et al. of lesions with “stiff rim sign” were higher than those of lesions without “stiff rim sign” (P<0.05). And the expression levels of Smad2/3, Erk1/2, p38 MAPK, JNK2, PI3K and AKT were corelated with that of TGF- β 1 (r=0.678, 0.633, 0.645, 0.611, 0.589, 0.663, P<0.0001).Conclusions: The expression levels of TGF-β1, et al. of breast lesions were corelated with the elastic characteristics, the expression levels of Smad2/3, Erk1/2, p38 MAPK, JNK2, PI3K and AKT were corelated with that of TGF- β 1, which speculated that TGF- β 1 might play an important role in the stiffness regulation of breast lesions through multiple signal transduction pathways.