Cell adhesion molecule 3 (CADM3), a transmembrane glycoprotein on cell membranes, plays a role in the way of ligand and receptor interaction. However, there are few studies on CADM3 in tumors, and how it works in breast cancer (BC) remains unclear. The Cancer Genome Atlas (TCGA) database and clinical samples were used to analyze CADM3 expression and its correlation with clinicopathological factors and prognosis. Its correlation with immune infiltration was analyzed by TCGA. The effects of CADM3 on proliferation and migration were investigated by cell clonal formation, CCK-8, cell scratch and transwell assay. Protein interaction network was prepared and the function prediction of related genes was conducted. The correlation between CADM3 and MAPK pathway was further explored by western blot experiment. The expression of CADM3 in BC tissues were significantly lower than that in adjacent normal tissues. High level of CADM3 was related to better prognosis of BC patients. CADM3 was an independent prognostic factor for BC. Expression of CADM3 was significantly associated with the status of ER and PR, age and PAM50 subtypes. CADM3 positively related to many immune infiltrating cells. Overexpression of CADM3 can notably reduce cell proliferation and migration. CADM3 was related to MAPK pathway and the phosphorylation of ERK1/2 and JNK1 was inhibited in BC cells with high CADM3. Our research reveals the clinical significance of CADM3 in BC and indicates the critical roles of CADM3 in immune infiltration and MAPK pathway.

中文翻译：

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CADM3在乳腺癌中低表达的临床意义及相关机制初步探讨

细胞粘附分子3（CADM3）是细胞膜上的一种跨膜糖蛋白，在配体和受体相互作用的方式中发挥作用。然而，关于CADM3在肿瘤中的研究很少，其在乳腺癌（BC）中的作用尚不清楚。利用癌症基因组图谱（TCGA）数据库和临床样本分析CADM3表达及其与临床病理因素和预后的相关性。通过TCGA分析其与免疫浸润的相关性。通过细胞克隆形成、CCK-8、细胞划痕和Transwell实验研究CADM3对增殖和迁移的影响。构建蛋白质相互作用网络并进行相关基因的功能预测。通过western blot实验进一步探讨CADM3和MAPK通路之间的相关性。 BC组织中CADM3的表达量显着低于癌旁正常组织。 CADM3水平高与BC患者较好的预后相关。 CADM3 是 BC 的独立预后因素。 CADM3的表达与ER和PR状态、年龄和PAM50亚型显着相关。 CADM3与许多免疫浸润细胞呈正相关。 CADM3的过度表达可以显着减少细胞增殖和迁移。 CADM3与MAPK通路相关，高CADM3的BC细胞中ERK1/2和JNK1的磷酸化受到抑制。我们的研究揭示了CADM3在BC中的临床意义，并表明CADM3在免疫浸润和MAPK通路中的关键作用。