title: Use expression with a variable r
body: <p>I am trying to label a plot with the following label:</p>
  
  <p>"Some Assay EC50 (uM)" where the "u" is a micro symbol. </p>
  
  <p>I currently have:</p>
  
  <pre><code>assay &lt;- "Some Assay"
  plot(0,xlab=expression(paste(assay," AC50 (",mu,"M)",sep="")))
  </code></pre>
  
  <p>But that gives: "assay EC50 (uM)" rather than the desired "Some Assay EC50 (uM)".</p>
  
  <p>Suggestions? Thanks.</p>
  
  <p>I also tried:</p>
  
  <pre><code>paste(assay,expression(paste(" AC50 (",mu,"M)",sep="")),sep="")
  </code></pre>