Humbert et al. [84] explored the value of ΔSUVmax after the first treatment cycle, in conjunction with various clinical and pathological markers (such as CA 15.3, ACE, CA-125 values, estrogen receptor, progesterone receptor, HER2 expression, Ki-67 index, androgen receptor, epidermal growth factor receptor (EGFR), Scarff-Bloom-Richardson (SBR) grade, and cytokeratin (CK) 5/6 tumor expression). This evidence concerns the gene ESR1 and neoplasm.