在UCSC Xena下载的临床信息中有tobacco_smoking_history这列信息，从1到5，知道是跟吸烟有关但不知道什么数字含义，google查到可能的解释
- Lifelong Non-smoker (less than 100 cigarettes smoked in Lifetime) = 1
- Current smoker (includes daily smokers and non-daily smokers or occasional smokers) = 2
- Current reformed smoker for > 15 years (greater than 15 years) = 3
- Current reformed smoker for ≤15 years (less than or equal to 15 years) = 4
- Current reformed smoker, duration not specified = 5
- Smoking History not documented = 7
另有图为证
https://groups.google.com/forum/#!topic/cbioportal/irEXZRj9Who
