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. Author manuscript; available in PMC: 2013 Oct 1.
Published in final edited form as: Cancer Epidemiol Biomarkers Prev. 2012 Aug 2;21(10):1735–1744. doi: 10.1158/1055-9965.EPI-12-0451

Figure 2. Age-at-incidence distribution and hazard rate over time are similar for aggressive tumors in Surveillance Epidemiology and End Results and young-like tumors in public tumor gene expression data.

Figure 2

(A) Grade was used to stratify ‘aggressive’ (poorly differentiated, grade 3) tumors and ‘less aggressive’ tumors, with a left shift in the age distribution for ‘aggressive tumors. (B) The young-like tumors mirror the left shift seen with aggressive tumors, providing a biological link between age and tumor aggressiveness. (C) Aggressive tumors have a unique hazard function in SEER data, with an early peak in hazard rate (2-5 years depending on tumor characteristic modeled) followed by a decreasing hazard rate, while less aggressive tumors (grade 1 or 2 in this example), have linearly increasing hazard rate with years following diagnosis. (D) Similarly, young-like tumors have a peak hazard early (prior to 5 years following diagnosis). Tumors with older-like gene expression show the characteristic linear increase in hazard rate over time. These hazard rate curves show that young-like tumors represent more aggressive breast cancer.