TABLE 2.

Subcellular Location and Functions of the Final Candidate Biomarkers

Protein Symbol	Subcellular Location	Interesting Functions for SCLC Progression
STMN1	Cytosolic MAP	Role in cell cycle progression and migration through microtubule depolymerization Possible role in axon formation during neurogenesis and neuron polarization Overexpression plays a role in tumor progression in various cancers, and contributes to chemoresistance
DPYL2	PMP and cytosolic MAP	Role in neuronal differentiation, axon guidance, neuronal growth, and cell migration in developing nervous system Associated with various neuropathologic or psychiatric disorders but not with cancer
RSSA	PMP (mainly), cytosolic and nuclear	Laminin receptor, role in cell adhesion to basal membrane and activation of signaling transduction pathways Overexpression correlated with invasive phenotype in various cancers
RUVB1	Nuclear (mainly) and PMP	AAA+ ATPase interacting with several transcription factors involved in carcinogenesis Role in tumor invasion by binding plasminogen at cell surface and increasing its activation into plasmin Overexpression observed in many cancers
GNAQ	PMP and cytosolic MAP	Couples cell surface transmembrane receptors to intracellular signaling pathways, including the MAPK pathway Activating mutations described in melanoma

MAP, membrane-associated protein; PMP, plasma membrane protein; SCLC, small-cell lung cancer.