ESR1 and neoplasm: In addition, the correlation between the IL-7 serum level and tumor size, histological type, histological grade, lymphovascular invasion (LVI) and perineural invasion (PNI), metastatic lymph nodes, and molecular markers such as estrogen receptor (ER), progesterone receptor (PR), amplification of Her-2/neu, Ki-67 proliferation index, molecular surrogate subtypes, age, and menopausal status has been evaluated.