What is Multiple Endocrine Neoplasias 1? Multiple Endocrine Neoplasias 1 (MEN1) is a cancer syndrome with several associated endocrine neoplasms. Learn more by hovering over the interactive image and watching our short video reviews. Study smarter with Pixorize. Retain more, gain a deeper understanding, and feel more prepared for your clerkships and the USMLE STEP 1/NBME shelf exams. Get early access to our upcoming releases, giveaways, and more by following us on social media!