FN1 and endometriosis: Lis-Kuberka et al. observed significantly higher concentration of fibronectin in the blood plasma (292.61 ± 96.17 mg/L vs. 226.55 ± 91.98 mg/L in controls) of women with endometriosis and the presence of fibronectin–fibrin complexes with a molecular mass of more than 1300 kDa, whereas there was a complete absence of these complexes in healthy women [39].