Figure 6
From: SPARC mediates metastatic cooperation between CSC and non-CSC prostate cancer cell subpopulations
Increased expression of SPARC in the epithelial component of primary prostate cancer associated with lymph node metastasis. (a) Immunohistochemical staining for SPARC of primary prostate cancer samples without (non-metastatic; samples i and ii) or with (metastatic; samples iii and iv) associated lymph nodes. A discontinuous line in sample iii delimits the stromal and epithelial tumoral components. Images are representative of stainings performed on 14 non-metastatic and 16 metastatic primary prostate cancer samples (case ID’s 28, 31, 38 and 59 from Additional file 1: Table S4). Size bar, 100 μm. (b) Real-time RT-PCR determinations of SPARC transcript levels in laser-microdissected epithelial or stromal components of non-metastatic or metastatic primary prostate cancer samples. Values represent transcript levels inferred from Ct values for SPARC normalized to Ct values for reference β2-microglobulin transcripts. Overall, non-microdissected transcript levels for the corresponding samples, determined in (c), are represented next to the relative levels for the microdissected components. Data are expressed as 2-ΔCt (microdissected samples, TaqMan assays) or 2-ΔCp (non-microdissected samples, UPL assays) using β2-microglobulin or 18S ribosomal RNA levels, respectively, as internal references. Note that value scales are different for microdissected (μd, left y-axis) or non-microdissected (non-μd, right y-axis) samples. (c) Real-time RT-PCR determinations of SPARC transcript levels in non-metastatic (n =15) or metastatic (n =17) primary prostate cancer samples. Data are expressed as 2-ΔCp, using 18S ribosomal RNA levels as an internal reference. No statistically significant differences are observed in median levels for non-metastatic vs. metastatic samples. (d) Plasma SPARC levels determined by ELISA in control individuals (n =4) and in patients with non-metastatic (n =10) or metastatic (n =14) prostate cancer. Asterisks denote statistically significant differences in median plasma SPARC levels between patients with metastatic prostate cancer and patients with non-metastatic disease or controls (two-tailed Mann–Whitney test).