PMC5836392_01
IL-34 expression in Nivolumab-resistant metastatic melanoma. (a) Scheme showing the chronologic progression of disease and treatment procedures. (b) Representative data of immunohistochemistry staining of IL-34 or melanoma antigens in primary or Nivolumab-resistant metastatic melanoma
41232_2018_60_Fig1_HTML.jpg
PMC5836392_01_41232_2018_60_Fig1_HTML.jpg
Fig1
Disease progression and treatment timeline are summarized in Fig. 1a. Interestingly, immunohistochemistry staining showed remarkable enhancement of IL-34 expression in Nivolumab-resistant metastatic melanoma compared to melanoma tissues at the primary site (Fig. 1b).
Enhanced IL-34 expression in Nivolumab-resistant metastatic melanoma correlates with increased numbers of infiltrating CD163+ cells. (a) Representative data of immunohistochemistry staining of IL-34 (left) or melanoma antigens (right) was compared between primary or Nivolumab-resistant metastatic melanoma tissues. Bar graph on the right shows mean fluorescence intensity of IL-34 or melanoma antigens staining in tumor areas. (b) Immunohistochemistry staining of CD163 was compared between primary or Nivolumab-resistant metastatic melanoma tissues. Bar graph on the right shows frequencies of CD163+ cells in the indicated samples. Data is shown as mean +- SEM. *P < 0.05
41232_2018_60_Fig2_HTML.jpg
PMC5836392_01_41232_2018_60_Fig2_HTML.jpg
Fig2
To further confirm this, quantification of IL-34 staining on randomly-selected tumor areas in each section was carried out, which showed statistically significant enhancement of IL-34 expression in refractory melanoma tissues (Fig. 2a). Consistent with these backgrounds, we found that high expression of IL-34 in refractory metastatic melanoma correlates positively with increased frequencies of CD163+ (a marker for M2-polarization) macrophages compared to primary melanoma (Fig. 2b).