What does the "X_OS_IND" column mean? I want to survival analysis using the subset of TCGA LUAD dataset, which identifier are located here.

&gt; head(LUAD_clinicalMatrix[,c("X_EVENT","X_OS_IND")])
  X_EVENT X_OS_IND
1      NA       NA
2       0        0
3       1        1
4       0        0
5       0        0
6       0        0

&gt; all(LUAD_clinicalMatrix$X_EVENT==LUAD_clinicalMatrix$X_OS_UNIT)
[1] FALSE


I want to know which identifier means the sample is alive or dead, and "1" means alive or dead?
According to this link, 1=death 0=censor and null=no data.