GPT gave me a definite answer, but I can't find any related information on the web. Pretty puzzled…
kkseaman, DCIS is generally tested only for ER and PR expression levels. HER2 is usually not measured because DCIS is noninvasive and Herceptin is not part of the standard of care so treatment would not be influenced by knowing the status. Those with ER+ or PR+ DCIS are sometimes prescribed tamoxifen or AIs to help prevent recurrence. Hope this helps.
Thanks a lot!
Most studies divide breast cancer into 4 main molecular subtypes:
These subtypes also appear in ductal carcinoma in situ (DCIS) .