CYR61 Confers the Sensitivity to Aromatase Inhibitor Letrozole in ER Positive Breast Carcinoma.
Studies have demonstrated that cysteine-rich 61 (CYR61) may be involved in tumor proliferation and invasion. However, the role of CYR61 plays in endocrine therapy response is largely unknown.



We tested the levels of CYR61 expression of 36 primary breast cancer patients who received neo-adjuvant endocrine therapy for at least 3 months by immunohistochemistry staining before and after administrating letrozole, an oral non-steroidal aromatase inhibitor (AI) for the treatment of hormone-responsive breast cancer. The expression levels of CYR61 and ki67 were compared between pre-treatment and post-treatment samples by using the paired t test. Chi-square test was used to determine the relationship between baseline CYR61 expression and clinical response.



In the clinical case series analysis, a positive correlation was observed between baseline CYR61 expression and clinical outcomes (p=0.02). CYR61 expression was significantly increased in the residual tumors after treatment (indicating insensitivity to endocrine therapy) compared with that in the baseline biopsy samples, which was irrespective of the efficacy of primary endocrine treatment. In addition, the ki67 level was significantly decreased after neo-adjuvant endocrine therapy, compared with that in the baseline samples.



This study provides evidence that CYR61 may confer the sensitivity to letrozole treatment and may offer an opportunity to target CYR61 to improve endocrine resistance in ER-positive breast cancer.
Xiaoqing
X
Jia
Guangyu
G
Liu
Jingyi
J
Cheng
Zhenzhou
Z
Shen
Department of Breast Surgery, Key Laboratory of Breast Cancer in Shanghai, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, 270 Dong-An Road, Shanghai 200032, P. R. China. Select country.
Zhimin
Z
Shao
D000368:Aged; D000369:Aged, 80 and over; D047072:Aromatase Inhibitors / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D055515:Cysteine-Rich Protein 61 / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D000077289:Letrozole; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009570:Nitriles / Q000494:pharmacology*; D011960:Receptors, Estrogen / Q000378:metabolism; D016896:Treatment Outcome; D014230:Triazoles / Q000494:pharmacology*
D047072:Aromatase Inhibitors; C501848:CCN1 protein, human; D055515:Cysteine-Rich Protein 61; D019394:Ki-67 Antigen; D009570:Nitriles; D011960:Receptors, Estrogen; D014230:Triazoles; D000077289:Letrozole
Aromatase inhibitor; CYR61/CNN1; breast cancer; estrogen receptor; sensitivity