Increased Level of Serum Leucine-Rich-Alpha-2-Glycoprotein 1 in Patients with Clear Cell Renal Cell Carcinoma

Abstract Background There are currently no useful serum markers for clear cell renal cell carcinoma (ccRCC). Therefore, early detection may be difficult because diagnosis is based only on imaging tests. There is also the problem of radiation exposure because multiple CT examinations are required to follow up on the course of treatment. In addition, the histological types of renal cell carcinoma (RCC) are roughly divided into ccRCC and non-clear cell RCC (non-ccRCC), but the treatment response to medications differs between the two, and it is important to distinguish between them. Therefore, we aimed to find a novel serum marker for RCC. Methods We measured the serum level of leucine-rich-alpha-2-glycoprotein 1 (LRG1) in 64 patients with clear cell RCC (ccRCC) and 22 patients with non-clear cell RCC (non-ccRCC) who underwent radical or partial nephrectomy, as well as 63 patients without cancer, by enzyme-linked immunosorbent assay. Results Median values of serum LRG1 and their inter-quartile ranges were 63.2 (42.8–94.2) µg/mL in ccRCC, 23.4 (17.7–29.6) µg/mL in non-ccRCC, and 36.0 (23.7–56.7) µg/mL in patients without cancer, respectively (ccRCC vs. non-ccRCC or patients without cancer: P < 0.001). In ccRCC, C-reactive protein (CRP) ( P = 0.0015), anaemia ( P = 0.0368), hypercalcemia ( P = 0.0233), and grade ( P = 0.0315) were independent predictors of serum LRG1 levels. To assess diagnostic performance, the area under the receiver operating characteristic curve of serum LRG1 was used to differentiate ccRCC from non-cancer and non-ccRCC, yielding values of 0.73 (95% CI: 0.6439–0.8169) and 0.91 (95% CI: 0.8195–0.9614), respectively. Conclusions LRG1 is a serum marker associated with inflammation as indicated by CRP, anaemia and hypercalcemia, and malignant potential in ccRCC. Clinically, the serum level of LRG1 may help differentiate ccRCC from non-ccRCC with excellent diagnostic accuracy.