Human nucleolin (NCL) is a multifunctional protein that is involved in diverse pathological processes. Recent evidences have shown that NCL is markedly overexpressed on the surface of most human cancer cells when compared to normal cells, being overexpressed in several malignant cells. Based on the exposed, the purpose of this pilot study is to investigate the expression pattern of NCL in canine malignant neoplasia and control groups. NCL expression at both messenger RNA and protein levels in the subcellular fractions were respectively detected by RT-PCR and western blotting, allowing to infer the NCL positivity rate in canine neoplasia. The identity of NCL amplicons obtained by RT-PCR was confirmed by Sanger sequencing and found to correspond to Canis lupus familiaris. Using flow cytometry, the blood cells expressing NCL from canine neoplasms were also identified using several cell surface markers and their levels quantified. These results showed that NCL expressed in lymphocytes, monocytes and neutrophils in dogs with malignant neoplasia is higher (> 50%) when compared with the control group. We found an increased expression of surface and cytoplasmic NCL in canine malignant neoplasia group, while nuclear NCL is predominantly found in the control group. Overall, this study discloses and identifies for the first time the presence of NCL in canine blood.

人核仁素（NCL）是一种多功能蛋白质，参与多种病理过程。最近的证据表明，与正常细胞相比，NCL 在大多数人类癌细胞表面显着过度表达，在几种恶性细胞中也过度表达。基于所暴露的信息，本初步研究的目的是调查 NCL 在犬恶性肿瘤和对照组中的表达模式。通过RT-PCR和蛋白质印迹分别检测亚细胞组分中信使RNA和蛋白质水平的NCL表达，从而推断犬肿瘤中NCL的阳性率。通过RT-PCR获得的NCL扩增子的身份通过Sanger测序进行确认，并发现其对应于Canis lupusamilis 。使用流式细胞术，还使用几种细胞表面标记物鉴定了表达犬肿瘤 NCL 的血细胞，并量化了它们的水平。这些结果表明，与对照组相比，患有恶性肿瘤的狗的淋巴细胞、单核细胞和中性粒细胞中NCL的表达较高(>50%)。我们发现犬恶性肿瘤组表面和细胞质 NCL 的表达增加，而细胞核 NCL 主要见于对照组。总体而言，这项研究首次揭示并鉴定了犬血液中 NCL 的存在。