MiR-21: an environmental driver of malignant melanoma?

Table 1 Environmental and lifestyle factors suggested to upregulate miR-21 signaling

MiR-21 stimulus	Mode of action [Refs.]
UV-irradiation	IL-6, STAT3; exosome release [15, 135–137]
Cell phone use	STAT3 upregulation [156]
Smoking	Increased miR-21 expression [67, 230]
Alcohol abuse	Increased miR-21 expression [226]
Pollution	Increased miR-21 expression by particulate matter [237]
Pollution	Increased miR-21 expression by diesel exhaust [238]
Arsenic	Increased miR-21 expression [65, 232–235]
Arsenic	Exosome release of bronchial epithelial cells [236]
Inflammation	IL-1β, IL-6, STAT3 [192–198]
Milk consumption	Uptake of milk-delivered exosomal miR-21 [16, 17, 162–168]
Milk consumption	Transfer of bovine miR-155, STAT3; IL-6 [169, 170, 173]
Obesity	Increased adipocyte miR-21 expression [210, 212]
Obesity	Adipocyte-derived exosome release [211–216]
Tumor diseases	Release of tumor cell-derived exosomes [44, 178–186]
Sedentary lifestyle	Physical exercise decreases miR-21 expression [229]
Higher age	Increased plasma miR-21 levels [189]

ISSN: 1479-5876