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.

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.

Lymph nodes (LN)are the main parts of the esophageal cancer metastasis,and the current status of LN is the important indicator of prognosis.LN metastasis appears in early stage of esophageal cancer.One side,LN metastasis easily appears in the regions near the tumor and some special areas.On the other side,LN metastasis has the characteristics of wide metastasis and skip metastasis.Therefore,the researches of the pattern of esophageal cancer lymph node metastasis can help to comform the scope of the esophageal cancer lymph node dissection and the target regions of radiotherapy.

Objective To detect the expressions of microRNA-126 (miR-126) and microRNA-7 (miR-7) in esophageal squamous cell carcinoma (ESCC) and to analyze their correlations with clinicopathologic features and prognosis of ESCC.Methods The expressions of miR-126 and miR-7 in 116 ESCC samples and matched normal tissue samples were detected by real-time PCR.Statistical analysis was used to find the relationships among the expressions of miR-126 and miR-7,pathological characteristics and prognosis.Results Low expression,normal expression and high expression of miR-126 were found in 73 (62.9％),35 (30.2％) and 8 (6.9％) carcinoma samples respectively.Low expression,normal expression and high expression of miR-7 were found in 52 (44.8％),35 (30.2％) and 29 (25.0％) carcinoma samples respectively.The disease-free survival in patients with low expression of miR-126 and miR-7 was shorter than that in patients with non-low expression (x2 =4.268,P ＜0.05 ; x2 =4.993,P ＜0.05).The low expression of miR-126 was correlated with tumor location,family history and drinking (x2 =14.564,P ＜ 0.05 ; x2 =5.691,P ＜ 0.05 ; x2 =4.971,P ＜ 0.05),but was uncorrelated with gender,age,diferentiation,infiltration,lymphatic metastasis and smoking (all P ＞ 0.05).The low expression of miR-7 was uncorrelated with pathological characteristics of ESCC (all P ＞ 0.05).Conclusion The low expressions of miR-126 and miR-7 may be related to the prognosis of patients with ESCC,and have a certain clinical detection significance.

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.