Table 1.

Candidate Genes As Potential Biomarkers for Common Symptoms in Oncology Patients^*

Candidate Gene Categories	Fatigue	Pain	Depression	Sleep Disturbance
Inflammatory pathways	Pro- and anti-inflammatory cytokine genes (e.g., IL1β, IL2, IL4, IL6, IL8, TNF)-α, interferon gamma)	Pro- and anti-inflammatory cytokine genes (e.g., IL1β, IL2, IL4, IL6, IL8, TNF)-α, interferon gamma)	Pro- and anti-inflammatory cytokine genes (e.g., IL1β, IL2, IL4, IL6, IL8, TNF)-α, interferon gamma)	Pro- and anti-inflammatory cytokine genes (e.g., IL1β, IL2, IL4, IL6, IL8, TNF)-α, interferon gamma)
Neuroendocrine pathways – can include genes associated with the following mechanistic pathways: hypothalamic-pituitary-adrenal (HPA) axis, five hydroxtryptamine (5HT) neurotransmitter dysregulation, circadian rhythm disruption, alterations in adenosine triphosphate (ATP) metabolism, vagal afferent activation, and glucocorticoid signaling	Genes associated with variations in serotonin, dopamine, and norepinephrine Clock genes and genes associated with circadian rhythm	COMT 5-HTT OPMR1	5HTT Clock genes and genes associated with circadian rhythm Genes associated with variations in serotonin, norepinephrine, and brain derived neurotrophic factor	Clock genes and genes associated with circadian rhythm Genes associated with variations in serotonin, norepinephrine, and dopamine

^*For reviews see - (Taheri 2004; McClung 2007; Turek 2007; Reyes-Gibby, Wu et al. 2008; Miaskowski 2009; Barsevick, Frost et al. 2010; Lau and Eley 2010; Shi, Cleeland et al. 2010; Lyon, McCain et al. 2011; Winkelmann and Kimura 2011)