The mechanical properties of living cells such as elasticity are highly relevant to the structural and molecular alterations induced by progression of diseases or by invasion of foreign organisms. Therefore, identification of the alternations of cells’ mechanical properties can be crucial to develop a complete knowledge of disease progression. Thus, we will have been developing multimodal imaging and analysis technologies, including a high-frequency acoustic radiation force impulse imaging and analysis method via photoacoustic detection, to probe mechanical properties of cells. In addition to the development of these technologies, we believe that it is highly important to explore biological applications of the developed imaging and analysis technologies. Thus, I will employ these technologies to measure mechanical properties of cancer cells for determination of invasiveness of cancer cells as well as for better understanding of molecular and biophysical mechanisms in the transformation of cancer cells from indolent to invasive phenotype.