IL-6 has been associated with fatigue in breast cancer survivors (Schubert et al., 2007; Saligan & Kim, 2012), the most prevalent and debilitating symptom among cancer survivors, and some studies showed that physical activity reduces fatigue in people with breast cancer specifically (Battaglini et al., 2014; Zou et al., 2014), and people with cancer in general (Meneses-Echávez, González-Jiménez & Ramírez-Vélez, 2015; Meneses-Echavez, Gonzalez-Jimenez & Ramirez-Velez, 2015). The gene discussed is IL6; the disease is cancer.