Although the main focus of this review is to discuss the role and importance of Gremlin-1 in cancer initiation and progression, it is worth mentioning that the expression and potential prognostic value of Gremlin-1 have been correlated to other diseases, such as type-2 diabetes [110], nonalcoholic fatty liver disease [110], obesity [111], pulmonary arterial hypertension [112], and Parkinson’s disease. The gene discussed is GREM1; the disease is obesity due to melanocortin 4 receptor deficiency.