SDC2 and breast cancer: In conclusion, our study is the first to underscore that MV-enriched EVs isolated from neoadjuvant chemotherapy-naïve obese breast cancer patients contained SDC2 and FN, serving as a potential non-invasive biomarker for detection of LNM, further, breast cancer tissue-derived SDC2 and FN mRNA levels act as diagnostic markers to differentiate breast cancer patients with pLNM from those with nLNM.