PIK3CA基因对人非小细胞肺癌A549细胞侵袭及迁移能力的影响

目的探讨PIK3CA基因对非小细胞肺癌侵袭及迁移能力的影响及可能机制。方法实时荧光定量PCR检测非小细胞肺癌组织、癌旁组织、非小细胞肺癌A549细胞与人支气管上皮细胞PIK3CA mRNA的表达,构建靶向PIK3CA基因的si RNA质粒,并转染至非小细胞肺癌A549细胞,实时荧光定量PCR技术与Westem blot方法分别检测PIK3CA mRNA与蛋白表达的变化,利用Transwell实验检测转染后细胞侵袭和转移能力的变化,Westem blot方法检测转染后A549细胞p-Akt蛋白表达变化。结果与癌旁正常组织比较,PIK3CA mRNA和蛋白表达水平在非小细胞肺癌组织显著上升(P0.05),A549细胞中PIK3CA mRNA和蛋白表达水平明显高于人支气管上皮细胞(P0.05)。PIK3CA基因沉默6h,A549细胞PIK3CA mRNA和蛋白表达水明显下降(P0.05);PIK3CA基因沉默48h,A549细胞侵袭和转移能力显著降低,p-Akt蛋白表达显著降低(P0.05)。结论 PIK3CA基因能够降低非小细胞肺癌侵袭及迁移能力,其作用机制可能与调控p-Akt蛋白表达有关。     

PIK3CA在人类癌症中的突变

【摘要】：大量的研究证实多种人类实体肿瘤中存在着PIK3CA突变。PIK3CA是一个致癌基因,在肿瘤细胞中, 其激酶活性增强, 能持续刺激下游AKT, 增加细胞侵袭和转移能力，因此在肿瘤的发生发展中起着至关重要的作用，同时对于临床诊断、治疗及预后有重要意义。抑制PIK3CA突变将是一种新兴的分子靶项肿瘤治疗手段。     

PIK3CA突变在人类癌症发生中的作用

大量的研究证实多种人类实体肿瘤中存在着PIK3CA突变.PIK3CA是一种致癌基因,在肿瘤细胞中,其激酶活性增强,能持续刺激下游AKT,增加细胞侵袭和转移能力,因此在肿瘤的发生发展中起着至关重要的作用,同时对于临床诊断、治疗及预后有着重要意义.抑制PIK3CA突变将是一种新兴的分子靶向肿瘤治疗手段.     

miR-363-3p 靶向PIK3CA 调节非小细胞肺癌细胞增殖、侵袭和迁移

目的:探索miR-363-3p靶向作用于磷脂酰肌醇激酶3催化亚单位(PIK3CA)对非小细胞肺癌(NSCLC)细胞A549增殖、侵袭和迁移的调控作用。方法:RT-PCR检测正常肺组织及NSCLC组织中miR-363-3p和PIK3CA基因表达,Spearman相关分析miR-363-3p和PIK3CA基因表达相关性,荧光素酶报告实验检测miR-363-3p和PIK3CA靶向关系。A549细胞分为mimic NC、miR-363-3p、pc-PIK3CA、miR-363-3p+pc-PIK3CA组,RT-PCR检测PIK3CA基因表达,Western blot检测PIK3CA、上皮性钙黏附蛋白(E-cadherin)、神经性钙黏附蛋白(N-cadherin)、G1/S特异性周期蛋白D1(Cyclin D1)、蛋白激酶B(AKT)、p-AKT蛋白表达,CCK8法检测细胞增殖,划痕愈合法检测细胞迁移,Transwell法检测细胞侵袭。结果:与正常肺组织相比,NSCLC组织中miR-363-3p表达下调,PIK3CA表达量上调,且miR-363-3p和PIK3CA基因表达呈显著负相关(P0.01)。在荧光素酶报告实验中,相比于WT PIK3CA+mimic NC组,WT PIK3CA+miR-363-3p组中荧光素酶活性显著降低(P0.01)。在细胞实验中,与mimic NC组比较,miR-363-3p组PIK3CA基因和蛋白表达、细胞增殖水平、细胞侵袭和迁移能力、N-cadherin、Cyclin D1蛋白表达水平、p-AKT/AKT比率显著降低,E-cadherin蛋白表达显著升高(P0.01),pc-PIK3CA组PIK3CA基因和蛋白表达、细胞增殖水平、细胞侵袭和迁移能力、N-cadherin、Cyclin D1蛋白表达,p-AKT/AKT比率显著升高,E-cadherin蛋白表达显著降低(P0.01);与pc-PIK3CA组比较,miR-363-3p+pc-PIK3CA组PIK3CA基因和蛋白表达,细胞增殖水平,细胞侵袭和迁移能力,N-cadherin、Cyclin D1蛋白表达,p-AKT/AKT比率显著降低,E-cadherin蛋白表达显著升高(P0.01)。结论:miR-363-3p可靶向作用于PIK3CA,抑制NSCLC细胞A549的增殖、侵袭和迁移。     

miR-203靶向PIK3CA对结肠癌SW480细胞增殖的影响

目的探讨miR-203对结肠癌SW480细胞增殖的影响及可能机制。方法采用脂质体介导的miR-203模拟物转染结肠癌SW480细胞,通过实时定量PCR进行验证,Western blot检测miR-203过表达后SW480细胞中p110α蛋白的表达。采用CCK-8法检测miR-203过表达后,SW480细胞增殖能力的变化,采用生物信息学网站预测PIK3CA是否为miR-203的靶基因,进一步应用双荧光素酶报告基因实验进行验证。结果 miR-203模拟物转染SW480细胞组,miR-203的表达水平显著升高,p110α蛋白表达下调,miR-203过表达能抑制SW480细胞体外增殖,生物信息学分析结果显示PIK3CA是miR-203的靶基因之一,双荧光素酶实验证实PIK3CA为miR-203的下游靶基因。结论 miR-203通过靶向调控PIK3CA抑制结肠癌SW480细胞增殖。     

胃癌组织中PIK3CA基因热点突变筛查及临床意义

目的 检测中国人群胃癌组织中PIK3 CA基因突变频率及热点突变模式,探讨PIK3 CA基因突变的临床意义.方法 应用荧光PCR法筛查胃癌PIK3 CA基因突变阳性病例,Sanger DNA测序法检测PIK3CA基因热点突变模式;统计分析PIK3 CA基因突变与胃癌临床病理特征之间的关系.结果 400例肿瘤标本中检测出PIK3 CA基因突变率为7.5％ (30/400),突变位点主要集中在第9外显子(E542K,E545K)和第20外显子(H1047R,H1047L);且PIK3 CA基因突变与肿瘤预后相关(P＜0.05),而与肿瘤大小、组织学分级、淋巴结状态、患者年龄等因素无关.结论 中国人群胃癌组织中PIK3CA基因突变具独特的突变频率与突变模式;PIK3 CA基因突变对于胃癌预后判断及基因靶向治疗具潜在临床价值.     

PIK3CA、PIK3CB、PIK3CD在胶质瘤中的表达及其意义

目的应用在线公共数据集,研究胶质瘤中PIK3CA、PIK3CB、PIK3CD表达及与预后的关系。方法通过ONCOMINE在线数据库对临床癌症样本中PIK3CA、PIK3CB和PIK3CD mRNA表达进行分析;应用GEPIA分析TCGA和GTEx数据库中的PIK3CA、PIK3CB和PIK3CD在胶质瘤和正常样本中的表达及与病人生存期的关系。通过cBioportal分析TCGA胶质瘤数据库中PIK3CA、PIK3CB、PIK3CD的突变、共表达以及调控网络。结果PIK3CA在胶质母细胞瘤(GBM)和低级别胶质瘤(LGG)中表达增加,其表达与GBM和LGG患者总体生存率(OS)和无病生存率(DFS)无显著相关。PIK3CB在GBM中表达水平下降,但差异不显著,在LGG中表达无明显变化,与GBM和LGG患者OS和DFS无显著相关。PIK3CD在GMB和LGG中表达水平下降,但差异不显著(P0.05),其表达与GBM患者的DFS显著相关,与LGG患者的DFS和OS显著相关(P0.05)。PIK3CA在GBM和LGG病例中突变比例较高,分别为12%和10%,PIK3CB和PIK3CD的突变较低;在GBM和LGG病例中,PIK3CB与PIK3CA的表达存在正相关;表达调控网络分析结果显示,此调控网络中包含51节点,包含PIK3CA和其它50个相关基因,IK3CA主要通过I3K/AKT发挥生物学作用。结论 PIK3CD在胶质瘤中表达下降,且与胶质瘤的预后密切相关。     

PIK3CA、CCL5、Survivin基因与甲状腺癌相关性的新发现

三种基因PIK3CA、CCL5、Survivin参与多种疾病过程,尤其与癌症关系密切.研究表明,PIK3CA、CCL5、Survivin基因多态性在甲状腺癌的发生、浸润、转移、治疗和预后方面发挥重要作用.     

252例结直肠癌组织中KRAS、NRAS、BRAF、PIK3CA的基因突变分析

目的分析结直肠癌(colorectal cancer,CRC)组织中KRAS、NRAS、BRAF和PIK3CA基因的常见突变类型及其与临床病理指标的关系。方法对252例CRC石蜡包埋组织进行DNA提取,采用Sanger测序法对KRAS、NRAS、BRAF和PIK3CA基因进行检测,分析各个基因的突变率与临床病理特征的关系,并统计各个基因的突变类型。结果 252例CRC中,KRAS、BRAF、NRAS和PIK3CA突变发生率在性别、年龄、肿瘤部位、病理分期和有无淋巴结转移上差异均无统计学意义(P0.05);检测阳性突变共140例(55.5%),其中KRAS 113例(44.8%),NRAS 1例(0.4%),BRAF 19例(7.5%),PIK3CA 28例(11.1%),包括PIK3CA与KRAS、NRAS、BRAF基因发生双突变21例(8.3%);KRAS的主要突变类型包括G12A、G12C、G12D、G12R、G12S、G12V、G13D、T20M、A59T、Q61H、Q61L、Q61P;NRAS仅有1例突变为G12D;BRAF的主要突变类型为V600E、D594G、K601E;PIK3CA的主要突变类型包括E542K、E545K、Q546K、Q546P、Q546R、M1043I、H1047R。PIK3CA与KRAS、NRAS、BRAF之间会发生交叉突变,但KRAS、NRAS、BRAF三者之间基本不存在交叉突变。结论 CRC中KRAS阳性突变率居高,PIK3CA次之,BRAF、NRAS突变率最低,且PIK3CA常与KRAS、NRAS、BRAF发生交叉突变。对CRC患者行KRAS、NRAS、BRAF、PIK3CA等多基因检测,可正确指导并选择抗EGFR单抗药,从而实现真正意义上的个体化靶向治疗。     

大肠癌组织中PIK3CA和PIK3CB的表达及意义

目的观察癌基因PIK3CA、PIK3CB在大肠癌组织中的表达及其相互关系,并分析PIK3CA和PIK3CB的表达对大肠癌患者预后的影响。方法采用免疫组化EnVision法染色并结合图像进行分析,探讨PIK3CA和PIK3CB在大肠癌组织及正常大肠黏膜组织中的表达;应用RT-PCR和Western blot技术分别检测PIK3CA mRNA和PIK3CB mRNA及其相应蛋白的表达;回访125例大肠癌术后患者,生存分析用Kaplan-Meier法,生存曲线用Log-Rank检验。结果在300例大肠癌蜡块组织及正常黏膜组织中,PIK3CA表达的平均光密度值分别为:10.087 9±2.148 7、6.937 6±2.065 3,PIK3CB表达的平均光密度值分别为:15.870 6±2.877 7、8.693 2±2.442 4。PIK3CA和PIK3CB在大肠癌组织中的表达具有相关性(r=0.68,P<0.05);RT-PCR检测结果显示,与正常大肠黏膜组织相比,大肠癌组织中PIK3CA mRNA和PIK3CB mRNA的表达水平均明显升高,且二者表达结果呈正相关(r=0.74,P<0.05);Western blot法检测发现PIK3CA和PIK3CB蛋白表达水平同样升高,二者表达结果呈正相关(r=0.71,P<0.05);生存分析显示PIK3CA和PIK3CB高表达与患者死亡风险具有明显相关性。结论 PIK3CA和PIK3CB在大肠癌组织中高表达,与正常黏膜组织中的表达相比差异较明显,且PIK3CA和PIK3CB在大肠癌的发生、发展中具有协同作用,PIK3CA、PIK3CB高表达亦是大肠癌患者预后相关的因素之一。检测大肠癌患者PIK3CA和PIK3CB的表达对于控制大肠癌的进展、确定大肠癌的靶点治疗及判断预后具有重要意义。     

Genetic alterations of phosphoinositide 3-kinase subunit genes in human glioblastomas

Genetic alterations of PI3K (phosphoinositide 3-kinase) subunits have been documented in a number of tumor types, with increased PI3K activity linked to gene amplification and mutation of catalytic subunits, as well as mutations of regulatory subunits. Among high grade gliomas, activation of the PI3K-AKT signaling pathway through loss of PTEN function is common. We therefore investigated whether genetic alteration of class IA PI3Ks might provide a mechanism for deregulation of this pathway in glioblastomas. We studied a series of glioblastomas with FISH to assess copy number of catalytic subunits (PIK3CA and PIK3CD) and with PCR-SSCP to screen for somatic mutations of conserved regions of both catalytic and regulatory subunits. FISH revealed frequent balanced copy number increases of both PIK3CA and PIK3CD, and one case showed an extra copy limited to PIK3CA. One glioblastoma exhibited a 9-bp deletion that encompassed the exon-intron junction of exon 12 of PIK3R1, documenting for the first time a mutation within a PI3K regulatory subunit in human glioblastoma. This deletion would be predicted to yield a truncated protein that lacks the inhibitory domain, resulting in increased PI3K activity. Furthermore, the case with selected PIK3CA copy number gain and the case with a truncating PIK3R1 mutation both featured AKT activation without PTEN mutation. These results suggest that genetic alterations of class IA PI3K subunit genes can occasionally play a role in human glioblastoma by activating the PI3K-AKT signaling pathway independently of PTEN mutation.     

PIK3CA gene mutations in endometrial carcinoma: correlation with PTEN and K-RAS alterations

Alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway are common in endometrial carcinoma. Inactivation of the tumor suppressor gene PTEN leads to a constitutively active PI3K pathway, which plays a role in the early steps of endometrial tumorigenesis. Other alterations in the PI3K/AKT pathway are mutations in the PIK3CA gene, which encode the p110alpha catalytic subunit of PI3K. PIK3CA mutations cluster to the helical (exon 9) and the kinase (exon 20) domains of the gene. In endometrial carcinomas, PIK3CA mutations have been found to coexist frequently with PTEN mutations, but it is not clear whether they occur in cells with monoallelic or biallelic inactivation of PTEN. In the present study we have evaluated PIK3CA mutational status in a series of 33 endometrial carcinomas, previously screened for microsatellite instability and mutations in PTEN, K-RAS, and CTNNB-1. The tumors were also evaluated for loss of heterozygosity on 10q23 and hypermethylation of the promoter region of PTEN/psiPTEN to assess the monoallelic or biallelic inactivation status of PTEN. PIK3CA mutations were detected in 8 (24%) of the 33 cases. Seven mutations were located in exon 20 and 1 in exon 9. PTEN alterations were found in 19 cases (57%). Biallelic inactivation of PTEN was demonstrated in 11 tumors, whereas 8 tumors exhibited alteration in only 1 of the 2 alleles. PIK3CA mutations coexisted with monoallelic alterations of PTEN in 4 cases (2 mutations and 2 allelic imbalances), with biallelic PTEN inactivation in 1 case (mutation and promoter methylation), and 3 tumors showed PIK3CA mutations in association with wild-type PTEN. PIK3CA mutations did not correlate with microsatellite instability or mutations in CTNNB-1. However, PIK3CA and K-RAS mutations (8 cases) were mutually exclusive alterations. In summary, the results confirm that PIK3CA mutations are frequent in endometrial carcinoma and support the hypothesis that PIK3CA mutations may have an additive effect to PTEN monoallelic inactivation in endometrial carcinoma.     

PIK3CA mutations in advanced ovarian carcinomas

PIK3CA belongs to the phosphatidylinositol 3-kinases (PI3Ks) family, which play an important role in proliferation, adherence, transformation and cell survival through the PI3K/AKT signaling pathway. Somatic activating mutations of this gene have recently been detected in several types of cancers. In the present study, 109 advanced ovarian carcinomas were analyzed for PIK3CA mutations in exon 9 and exon 20 by direct sequencing. Activating missense mutations were observed in 4 of the 109 tumors in addition to one variant leading no change of the PIK3CA protein. Two of the cases with mutations were mucinous and clear cell tumors, suggesting that PIK3CA mutations are more common in these rare histological types.     

PI3K Signaling in Glioma—Animal Models and Therapeutic Challenges

The PI3 kinase (PI3K) family plays a complex role in cell biology and metabolism. Signaling through the PI3Ks is frequently activated in many human cancers, including glioblastoma, because of gain-of-function mutations in PIK3CA or loss of PTEN. Experiments involving genetic mouse models and small molecule inhibitors have helped to elucidate the roles of the regulatory and catalytic subunits of PI3K in metabolism and cancer. Downstream of PI3K is Akt, a critical effector of growth, proliferation and survival. The suggested dependence of glioblastoma tumors on PI3K signaling implies that PI3K inhibitors should lead to effective killing of these cancer cells, but that has been shown not to be the case. The engagement of other survival pathways in response to PI3K inhibition prompts the need to develop combination therapies that promote cytotoxicity in cancer cells.     

Rare PIK3CA hotspot mutations in carcinomas of the biliary tract

Somatic mutations of the PIK3CA gene, which encodes the p110alpha catalytic subunit of phosphatidylinositol 3-kinase (PI3K), are frequent in various cancer types. The majority of mutations cluster at hotspots within exons 9 and 20, which encode the helical and kinase domains of p110alpha. PIK3CA mutations in bile duct and gallbladder carcinomas have not been reported yet. In this study, we analysed 118 carcinomas of the biliary tract and the liver (45 intra- and extrahepatic cholangiocarcinomas (CCA), 23 gallbladder carcinomas, 50 hepatocellular carcinomas) for PIK3CA hotspot mutations using polymerase chain reaction and direct DNA sequencing. PIK3CA missense mutations were found in one of 11 intrahepatic CCA (E545K, 9%), one of 23 gallbladder carcinomas (E542K, 4%), and one of 50 hepatocellular carcinomas (H1047R, 2%). All three mutations represent hotspot mutations, which also occur in other cancer types. PI3K pathway activation in hepato-biliary carcinomas was analyzed using immunohistochemistry for the downstream targets eIF4-E and phosphorylated 4E-BP1 on tissue microarrays. eIF4-E expression was found in 3/13 intrahepatic CCA (23%), 9/38 extrahepatic CCA (24%), 12/34 gallbladder carcinomas (35%), and 9/61 hepatocellular carcinomas (15%). 4E-BP1 phosphorylation was observed in 1/13 intrahepatic CCA (8%), 8/38 extrahepatic CCA (21%), 15/34 gallbladder carcinomas (44%), and 16/61 hepatocellular carcinomas (26%). These results indicate that somatic PIK3CA mutations contribute to the frequent activation of the PI3K/AKT pathway in carcinomas of the biliary tract and liver.     

PIK3CA cancer mutations display gender and tissue specificity patterns

The occurrence of oncogenic alleles can display striking tissue specificity. For example KRAS mutations are very frequent in pancreatic cancers but relatively rare in melanomas. The opposite is true for BRAF mutations. Somatic mutations in the gene encoding for the phosphatidylinositol 3-kinase (PI3KCA) catalytic subunit, PIK3CA, occur at high frequency in many solid cancers. We have examined whether PI3K oncogenic mutations (exons 9 and 20) might exhibit gender and/or tissue specificity. By examining large cohorts of breast and colorectal cancers affecting both men and women we found that the pattern of PIK3CA mutations is distinctive. In colorectal cancers, PIK3CA (but not KRAS, APC, or TP53) mutations display a gender bias occurring at higher frequencies in women. We also found that male breast cancers display PIK3CA mutations at an overall frequency similar to that observed in female breast tumors. In male breast cancers, however, PIK3CA mutations are found mainly in exon 20. We conclude that PI3KCA mutations affecting exons 9 and 20 display gender- and tissue-specific patterns, thus suggesting that the different amino acid changes could exert distinct functional effects on the oncogenic properties of this enzyme. Furthermore, we propose that sexual dimorphisms and tissue specific factors might directly or indirectly influence the occurrence of PI3KCA cancer alleles.     

Mutation and genomic amplification of the PIK3CA proto-oncogene in pituitary adenomas

The tumorigenesis of pituitary adenomas is poorly understood. Mutations of the PIK3CA proto-oncogene, which encodes the p110-α catalytic subunit of PI3K, have been reported in various types of human cancers regarding the role of the gene in cell proliferation and survival through activation of the PI3K/Akt signaling pathway. Only one Chinese study described somatic mutations and amplification of the PIK3CA gene in a large series of pituitary adenomas. The aim of the present study was to determine genetic alterations of PIK3CA in a second series that consisted of 33 pituitary adenomas of different subtypes diagnosed by immunohistochemistry: 6 adrenocorticotropic hormone-secreting microadenomas, 5 growth hormone-secreting macroadenomas, 7 prolactin-secreting macroadenomas, and 15 nonfunctioning macroadenomas. Direct sequencing of exons 9 and 20 assessed by qPCR was employed to investigate the presence of mutations and genomic amplification defined as a copy number ≥4. Previously identified PIK3CA mutations (exon 20) were detected in four cases (12.1%). Interestingly, the Chinese study reported mutations only in invasive tumors, while we found a PIK3CA mutation in one noninvasive corticotroph microadenoma. PIK3CA amplification was observed in 21.2% (7/33) of the cases. This study demonstrates the presence of somatic mutations and amplifications of the PIK3CA gene in a second series of pituitary adenomas, corroborating the previously described involvement of the PI3K/Akt signaling pathway in the tumorigenic process of this gland.     

Mutations in FGFR3 and PIK3CA, singly or combined with RAS and AKT1, are associated with AKT but not with MAPK pathway activation in urothelial bladder cancer

Different members of the phosphoinositide 3 kinase - serine threonine protein kinase (PI3K-AKT) pathway are altered in bladder cancer. Fibroblast growth factor receptor 3 (FGFR3) mutations characterize the low-grade tumors, and RAS genes are mutated in approximately 13% of all bladder tumors. Interestingly, a percentage of bladder tumors have alterations in more than 1 PI3K-AKT or rat sarcoma viral oncogene homolog-RAF mitogen activated protein kinase (RAS-MAPK) pathway gene or their upstream regulators, but some combinations are mutually exclusive. We analyzed mutations in FGFR3, phosphoinositide 3 kinase catalytic alpha polypeptide (PIK3CA), v-akt murine thymoma viral oncogene homolog 1 (AKT1), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), v-Ha-ras Harvey rat sarcoma viral oncogene homolog (HRAS), and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) in 88 urothelial cell carcinomas and the immunohistochemical expression of phospho-v-akt murine thymoma viral oncogene homolog (AKT) and mitogen-activated protein kinase 1 and 2 (pERK1/2) in 80 and 77 urothelial cell carcinomas, respectively. Approximately 43% and 20.5% of tumors presented 1 and 2 mutated genes, respectively. FGFR3 mutations were more frequent alone, whereas PIK3CA mutations were associated with another mutated gene (FGFR3 and KRAS). Overall, mutated FGFR3 (FGFR3(mut)) and mutated FGFR3 (FGFR3(mut))-mutated PIK3CA (PIK3CA(mut)) genotypes were associated with low-grade bladder tumors and mutated PIK3CA (PIK3CA(mut))-mutated KRAS (KRAS(mut)) and mutated AKT1 (AKT1(mut)) were only present in high-grade tumors. There are no mutated FGFR3 (FGFR3(mut))-mutated RAS (RAS(mut)) nor mutated PIK3CA (PIK3CA(mut))-mutated AKT1 (AKT1(mut)) combinations. Fifty percent and 56% of tumors showed high levels of pAKT and pERK1/2, respectively. High levels of pAKT were associated with total mutations, FGFR3(mut), and PIK3CA(mut) tumors but not with tumor grade or stage. Wild-type tumors presented significantly higher pERK1/2 expression. Mutations in FGFR3 and FGFR3-PIK3CA but not single PIK3CA mutations characterize low-grade bladder tumors. Single FGFR3 or PIK3CA mutations and the different mutation combinations FGFR3-PIK3CA/AKT1 and PIK3CA-RAS can activate the AKT but not the MAPK pathway. Other genes different from FGFR3 may be related with the pERK activation in bladder tumors.