Figure 1.

IHC staining of ATR in an osteosarcoma TMA correlates to chemo-response, tumor progression, and patient prognosis. ATR and activated pATR expression in a TMA constructed from 70 osteosarcoma patient samples evaluated by IHC. (A) Representative images of the TMA ATR and pATR staining (200×; scale bar: 100 µm). Four subgroups were defined according to ATR staining intensity in the cytoplasm. The stained samples were then subdivided into either the low (0 or 1+) or high (2+ or 3+) ATR expression group. Six subgroups were defined based on the percentage of cells with positive nuclear pATR staining. Again, patient samples were categorized as being in the low (staining score <3) or high (staining score ⩾3) pATR expression group. (B) Pie chart represents the relative frequencies of different ATR and pATR expression amongst the osteosarcoma TMA specimens. (C) Association of ATR and pATR expression with chemo response according to percentage of histological tumor necrosis of the osteosarcoma tissues. (D) Comparison of ATR and pATR IHC staining scores among primary, metastatic, and recurrent osteosarcoma samples. (E) Comparison between ATR and pATR IHC staining scores in osteosarcoma patients that survived (survival) and those that did not (non-survival). (F) Inverse correlation between ATR and pATR expression and osteosarcoma patient clinical follow ups (based on the Spearman’s rank correlation). (G) Kaplan–Meier overall-survival curve of osteosarcoma patients sub-grouped as in the ATR or pATR low-expression group and high-expression group. (H) Kaplan–Meier disease-free survival curves of osteosarcoma patients with low and high expression of ATR or pATR. *p < 0.05 ** p < 0.01.

ATR, ataxia-telangiectasia and Rad3 related protein kinase; IHC, immunohistochemistry; pATR, phospho-ATR; TMA, tissue microarray.