Hello, I have been searching for over a year for what might have caused LCH or langerhans cell histiocytosis. And finding much information now. I know apoquel was the culprit. I was told that this is an extremely rare form of cancer. Started out with an ulcerated sore on my dogs side.  It spread like wildfire and due to the pain he was in and his whole body ending up covered in ulcerated tumors I had to make the choice for his suffering to end8. I finally got the answer that I was praying for through Relentless internet search but now I am so angry they are continuing to run commercials for this medication and handing it out like candy or I should say dog treats. I am trying to figure out if there is any way to stop is medication from being manufactured. If anyone could give me some advice on where to begin I would greatly appreciate it. Thank you, Jill