Objective: To investigate the correlations of laminin subunit gamma 3 (LAMC3) expression with prognosis of ovarian cancer (OC). Methods: LAMC3 protein expression was measured using immunohistochemical streptavidin-peroxidase-biotin connection method (IHC). Gene expression and related clinical data in the cancer genome atlas (TCGA) cohort and clinical proteomic tumor analysis consortium (CPTAC) were applied to analyse the correlation between gene and protein expressions and clinical outcomes. Correlations between LAMC3 and clinicopathological factors were evaluated using the Pearson χ2 test (2-sided). The probability of survival and significance was calculated using the Kaplan-Meier plot. The functional clustering of biological pathways enriched from co-expressed genes of LAMC3 was used to explore the possible mechanisms that LAMC3 might contribute to poor prognosis. Results: Based on the IHC results of 216 OC tissues or ovaries (including 208 tumors and 8 normal tissues) and 51 OC tissues (including 24 chemotherapy-resistant and 27 sensitive tissues), and the protein expression data from CPTAC (including 100 primary tumors and 25 normal tissues), the results showed that the protein expression of LAMC3 was significantly decreased in OC tissues compared with normal, decreased in advanced-stage tissues compared with early-stage tissues, and decreased in drug-resistant tissues compared with sensitive tissues (all P<0.05). Furthermore, low expression of LAMC3 protein was significantly associated with poor disease-free survival (DFS) and overall survival (OS) in 51 OC tissues (P<0.01), consistent with the results that the low levels of LAMC3 mRNA predicted short DFS and OS in 489 OC tissues of the TCGA cohort (P<0.05). The results suggested that low expression of LAMC3 might be the adverse factors for OC development, such as drug resistance and advanced tumors, and might be a risk indicator for prognosis. Moreover, functional clustering of biological pathways enriched from the co-expressed genes of LAMC3 in TCGA ovarian cohort indicated that LAMC3 potentially involved in regulation of OC via oncogene-pathways such as Ras associated protein 1 (Rap1), mitogen-activated protein kinase (MAPK), Ras and cell adhesion-related pathways such as extra cellular matrix (ECM)-receptor interaction and focal adhesion. It indicated that LAMC3 might contribute to short survival and tumor progression by regulation of the above pathways. Conclusion: Low expression of LAMC3 is related to poor prognosis and malignant progression in OC, and thus it is expected to be a new prognostic marker and therapeutic target for clinical treatment.
目的： 探讨层粘连蛋白γ3亚基（LAMC3）表达与卵巢上皮性癌（卵巢癌）患者不良预后的相关性。 方法： 应用免疫组化SP法检测卵巢癌组织（包括商品化标本和本研究标本）中LAMC3蛋白的表达，其中商品化标本为购买的卵巢组织微阵列芯片（包括208份卵巢癌组织和8份癌旁正常卵巢组织）、本研究标本为2005年4月至2012年12月在广西医科大学附属肿瘤医院手术治疗的51份Ⅰc~Ⅳ期卵巢癌组织标本（包括24份化疗耐药组织和27份化疗敏感组织）；使用癌症基因组图谱（TCGA）队列数据（489份卵巢癌组织）及临床蛋白质组学肿瘤分析协作组（CPTAC）蛋白质组学数据库（包括100份卵巢癌组织和25份癌旁正常卵巢组织）等开放数据对LAMC3表达与卵巢癌患者预后的相关性进行分析；Pearson χ²检验（双侧）分析本研究标本（51份卵巢癌组织）及TCGA队列数据（489份卵巢癌组织）中LAMC3表达与临床病理指标的相关性；Kaplan-Meier法绘制生存曲线，分析LAMC3表达与无疾病生存时间（DFS）和总生存时间（OS）的关系；采用共表达基因的通路富集和功能聚类分析，探讨LAMC3调控卵巢癌患者预后的可能分子机制。 结果： 商品化标本和本研究标本的免疫组化SP法检测结果及CPTAC蛋白质组学数据库中的数据显示，与癌旁正常卵巢组织、早期（Ⅰ~Ⅱ期）卵巢癌组织及卵巢癌化疗敏感组织相比，LAMC3表达在卵巢癌组织、晚期（Ⅲ~Ⅳ期）卵巢癌组织及卵巢癌化疗耐药组织中均显著下调（P<0.05）；且在本研究标本（51份卵巢癌组织）中，LAMC3蛋白低表达与卵巢癌患者的不良DFS及OS显著相关（P<0.01），而这一结果在TCGA队列数据（489份卵巢癌组织）中进一步得到验证，发现LAMC3 mRNA低表达也与不良DFS及OS显著相关（P<0.05）。基于TCGA队列数据（489份卵巢癌组织）中LAMC3共表达基因的通路富集和功能聚类分析表明，卵巢癌中LAMC3基因潜在调控Ras相关蛋白1（Rap1）、有丝分裂原活化蛋白激酶（MAPK）、Ras等癌基因信号通路及细胞外基质（ECM）-受体相互作用和黏着斑等细胞黏附相关通路，进而影响卵巢癌的进展和患者的不良预后。 结论： LAMC3低表达与卵巢癌患者的不良预后和肿瘤进展相关，有望作为新的卵巢癌治疗靶点和预后标志物应用于临床。.