Histological changes of tumor tissue post-PDT by H&E staining (×200).

<p>The necrotic areas of tumor dyes red isotropicly undergoing light microscopy. <b>A.</b> The tumor surface appeared the widespread necrosis and incrustation region in HMME-PDT group under gross appearance. <b>B.</b> The widespread necrotic areas and significant inflammatory cells infiltrative growth were observed in tumor tissues in the HMME-PDT group.