Cancer is frequently considered to be a disease of cell cycle. Recently, it is reported that the transfer of functional ceil cycle regulators into caneer cells via vectors has the potential to intervene tumorigenesis development. This therapeutic strategy might allow cancer cells to regain missing or dysfunctional gene expression due to inhibiting aberrant proliferation or restoring phenotypes defects. As an important negative effecter of cell cycle progression, p21cip1 not only plays central roles in cell proliferation,differentiation, senescence and apoptosis, but also associates with tumor regression. In this review, we will mainly focus on discussing some recent progress in novel strategies for cancer biological therapy, related with the functions of p21cip1 in cell proliferation and apoptosis during tumorigenesis.

Genetic polymorphisms are thought to be associated with the individual difference in the esophageal cancer treatment.A large number of evidences show that 5-FU and cisplatin metabolism,apoptosis and angiogenesis related gene SNPs are associated with the therapeutic sensitivity of esophageal cancer.

The epidermal growth factor receptor tyrosine kinase inhibitor(EGFR-TKI)is a kind of high-efficiency and low-toxicity tumor molecular targeted drugs.It becomes a research hotspot in non-small cell lung cancer (NSCLC)treatment because of its unique curative effect and well tolerance.EGFR-TKI is mainly applied to the second and third line treatment of patients with advanced NSCLC or first line treatment of EGFR mutation patients.With the development of research,the indications of EGFR-TKI expand unceasingly.The preoperative neoadjuvant therapy is likely to become a new kind of treatment mode.

miRNAs are endogenous short RNA molecules widely distributed in eukaryotic organisms.They are closely related to tumor development. One good example is miR-21. It is overexpressed in a variety of tumor tissues, suggesting that miR-21 may have significant carcinogenic activities and act as a oncogene.Many studies confirm that overexpression of miR-21 has great indication in the development, diagnosis, biological treatment and prognosis of gastrointestinal cancer.

hMSH6 is one of the most important members in the mismatch repair family. Its polymorphism is closely related to the pathogenesis and development of neoplasm, particularly in colorectal cancer and endometrial cancer. Moreover, it has been suggested to play a more important role in endometrial cancer compared with hMLH1 and hMSH2.

Variants of gene loci on susceptibility genes are the major individual susceptibility factors of esophageal squamous cell carcinoma (ESCC) in China.Some of the gene loci participate in the DNA damage and repair,and some are related with cancer suppressor genes,metabolism enzymes,trace elements and smoking.The single nucleotide polymorphisms of these susceptibility genes are closely correlated with the genesis of ESCC.

Researches find that microRNAs(miRNAs) participate in cell proliferation,differentiation and apoptosis.Dysregulation of miRNA exist in almost all kinds of tumors,including esophageal cancer.MiRNAs bind to mRNA of oncogene or tumor suppressor gene by perfectly or partly base-pair complementarity,and then,promote mRNA degradation or inhibit translation of target mRNA.Recently studies have comfirmed that miRNA functions as a significant regulator in esophageal cancer and it is involved in tumorigenesis,development and prognosis.MiR-21 binds to programmed cell death 4(PDCD4) mRNA and inhibits the translation of PDCD4,then promotes tumorigenesis of esophageal cancer.MiR-106-25 polycistron is activated by genomic amplification,and then suppresses the expressions of P21 and Rim,and subsequently promotes the occurrence and progress of esophageal cancer.

In recent years,a large number of researches show that the tumor related gene promoter hypermethylation is an important reason of esophageal adenocarcinoma and closely associated with the differentiation,invasion,metastasis,staging and prognosis of tumors.It might be used as a neww target for the clinical detection and therapy of esophageal adenocarcinoma.

ObjectiveTo investigate the methylation status of multiple genes in plasma and tumor tissues and its application in molecular diagnosis of esophageal squamous cell carcinoma (ESCC).Methods Methylation specific polymerase chain reaction (MSP) was used to detect methylation status of 5 tumor suppressor genes,such as adenomatous polyposis coli ( APC ),retinoic acid receptor-beta2 ( RARβ2 ),E-cadherin (CDH1),cyclin-dependent kinase inhibitor4A (p16INK4α) and ras association domain family member 1 A (RASSF1A) in tumour tissues,adjacent normal tissues and plasma which obtained 1 d preoperative and 7 d postoperative in 76 cases with ESCC.60 healthy volunteers were randomly selected as a control which were age-matched and sex-matched.Chi square test was used to analyze DNA methylation rates of 5 genes in various groups of tissue and plasma samples; Kappa test was used to compare the consistency of DNA methylation in the plasma samples and tissue samples,and their correlation was analyzed by Spearman correlation test; Receiver operating characteristic curve (ROC) was used to evaluate the sensitivity and specificity for single gene detection and 5 genes joint detection for diagnosis of esophageal squamous cell carcinoma.ResultsThe methylation rates of APC,RARβ2,CDH1,p16INK4α and RASSF1A in tumour tissues of patients with ESCC were 44.7％ ( 34/76),72.4％ ( 55/76 ),72.4％ (55/76),86.8％ ( 66/76 ),55.3％ (42/76),respectively,which were significantly higher than that in the corresponding adjacent normal tissues [ 6.6％ ( 5/76 ),3.9％ ( 3/76 ),3.9％ ( 3/76 ),3.9％ ( 3/76 ),2.6％ ( 2/76 ),x2 =29.01,75.39,75.39,105.34,57.18,all P ＜ 0.001 ].The methylation rates of above 5 genes in patients' plasma were 42.1％ ( 32/76 ),63.2％ ( 48/76 ),63.2％ ( 48/76 ),71.1％ ( 54/76 ),50.0％ ( 38/76 ),respectively,which were significantly higher than that of control group [3.3％ (2/60),3.3％ (2/60),1.7％ ( 1/60),3.3％ (2/60),1.7％ (1/60),x2 =26.88,51.62,55.01,63.48,38.30,all P ＜ 0.001 ].The methylation consistency was favorable or well between plasma and tumour tissues in patients with ESCC ( Kappa value was 0.679,0.791,0.791,0.542 and 0.895,respectively.all P ＜0.001 ).In single-gene detection for patients' plasma,methylation,the sensitivity of 5 genes was 42.1％ ( 32/76 ),63.2％ ( 48/76 ),63.2％ ( 48/76 ),71.1％ ( 54/76 ),50.0％ ( 38/76 ),respectively.The specificity was 96.7％ ( 58/60 ),96.7％ ( 58/60 ),98.3％ (59/60),96.7％ (58/60),98.3％ (59/60),respectively.The area under curve (AUC) of ROC was 0.694 [95％ confidence interval( CI)0.606 - 0.782 ) ],0.799 ( 95％ CI 0.723 - 0.875 ),0.807 ( 95％CI 0.733 - 0.882),0.839 ( 95 ％ CI 0.769 - 0.908 ) and 0.742 ( 95 ％ CI 0.659 - 0.824 ),respectively.In united testing of 5 genes,the sensitivity was 80.3％ and the specificity was 88.3％,AUC was 0.843 (95％CI 0.773 -0.913 ).The sensitivity of united testing was significantly higher than that of single-gene detection of APC and RASSF1A(x2 =23.30,15.33 ; P ＜ 0.001 ),except RARβ2,CDH1 and p16INK4α (x2 =5.48,5.48,1.75; P =0.019,0.019,0.186);There was no significant differences in specificity between united testing and single-gene detection (x2 =1.922,1.922,3.348,1.922,3.348,all P ＞ 0.05 ).Conclusions The methylation consistency is favorable or well between tumour tissues and plasma in patients with ESCC.There is no significant superior in diagnosing ESCC with united testing of multiple tumor suppressor genes methylation in plasma than with single-gene detection.But the sensitivity of the former is better than the latter.

With depth understanding of the mechanism of human leukocyte antigen G (HLA-G) protein,more and more studies have found that HLA-G is closely related with tumor immune escape.Numerous studies have shown that the expression of HLA-G protein and mRNA could be detected in patients with cancer.