Renal cell carcinoma: the search for a reliable biomarker

Abstract

One particular challenge in the treatment of kidney tumors is the range of histologies and tumor phenotypes a renal mass can represent. A kidney tumor can range from benign (e.g., oncocytoma) to a clinically indolent malignancy (e.g., papillary type I, chromophobe) to aggressive disease [e.g., papillary type II or high-grade clear cell renal cell carcinoma (ccRCC)]. Even among various subtypes, kidney cancers are genetically diverse with variable prognoses and treatment response rates. Therefore, the key to proper treatment is the differentiation of these subtypes. Currently, a wide array of diagnostic, prognostic, and predictive biomarkers exist that may help guide the individualized care of kidney cancer patients. This review will discuss the various serum, urine, imaging, and immunohistological biomarkers available in practice.

Keywords: Imaging biomarker; immunohistochemistry; kidney cancer; liquid biopsy; molecular biomarker; radiomics; renal cell carcinoma (RCC); serum biomarker; tissue biomarker; urine biomarker.

Figure 1

Multi-parametric MRI. (A) Dynamic contrast-enhanced MRI; (B) 3D perfusion parametric map characterizing the microcirculation of a kidney tumor. Red correlated with high perfusion, blue with low perfusion. Modified with permission from Farber et al. (13). MRI, magnetic resonance imaging.

Figure 2

Morphology and immunohistochemistry of ccpRCC. (A) On histology, ccpRCC exhibits a papillary architecture under low magnification (HE, ×40); (B) under higher magnification, the tumor shows cells with clear cytoplasm with luminally oriented low grade nuclei, away from the basement membrane (HE, ×200); (C) by immunohistochemistry, ccpRCC shows strong membranous staining for CK7 (×200); (D) strong “cup shaped” staining for CA-IX with characteristic absence of staining along the lumen (×200). ccpRCC, clear cell papillary renal cell carcinoma; CA-IX, carbonic anhydrase IX.