Regression coefficient for downstream analysis from lasso regression for survival analysis

Question

[1769mkc]

I have one dataset which I have used to build and generate a model for survival prediction.

Here I get like 40 genes as my predictor which I have tested both in my test and train dataset so for this I have used the TCGA cohort. Now to test in an independent data I have chosen another patient cohort bigger one beatAML dataset which i want to make it as my validation dataset. Now the issue I'm facing is for some of the gene which i have got coefficient are missing in my validation data set.

So is it correct to eliminate those genes which are not present in my validation cohort and go ahead with the ones which are present.?