LC3A Predicts The Sensitivity Of Concurrent Chemoradiotherapy In Esophageal Squamous Cell Carcinoma

Part Ⅰ:The Expression and Significance of LC3A in Esophageal Squamous Cell CarcinomaObjective:Autophagy is a selfdegradation process in which intracell membrane structures sequester the superfluous and damage long-life proteins and organelles that are then delivered to lysosomes for degradation. The selfdigestion surpplies materials(such as amino acids) and energy. Macroautophagy is the usually referred autophagy. Autophagy is an evolutionarily conserved process from yeast to mammalians. The basal role of autophagy is to maintain homeostasis. In growth factors deprivation, accumulation of unfolded proteins, hungery induced stresses, autophagy is up-regulated and acts as a cytoprotective mechanism. It has been shown that autophagy is involved in tumorigenesis, tumor development, and the role of it in tumor therapy has attracted more and more attention. A lot of evidence has proven that in some life-threatening stresses, autophagy is activated and the activation leads to different fates with the kinds of stresses and tumor types. The general notion is that autophagy contributes to tumor cell survival during stresses and anti-cancer therapies. The autophagy activation makes tumor cells more resistant to anti-cancer drugs and ionizing radiation. Autophagy inhibition is a potential anticancer strategy. Microtubule-associated protein light-chain3(LC3)is one important component of the autophagosomes which has three isoforms,LC3A,LC3B,and LC3C. When autophagy occurs, cytosolic form LC3-Ⅰ converts to membrane form LC3A-Ⅱ.This change in intacellular localization of LC3protein correlates with autophagy activity. As one of LC3three isoforms and marker of autophagy activity, LC3A correlates well with the prognosis of a lot kinds of malignancies, such as lung cancer, colon cancer. This study aims to analyze the relationships between LC3A expression and clinicopathological factors, prognosis, and explores the prognostic value of LC3A in esophageal squamous cell carcinoma(ESCC).Materials/Methods:From our clinical archives, I selected243ESCC patients who were treated with radical surgery in the Department of Oncology of the Affiliated Hospital of Binzhou Medical College between January2005and December2008.All patients had no any treatment before radical surgery.158patients with stage Ⅱ/Ⅲ (TanyN+Mo or T3.4NanyMo) ESCC underwent adjuvant concurrent chmoradiotherapy, sequential chemoradiotherapy, or radiotherapy alone after surgery. Tissue specimens which obtained from paraffin-embedded tumor tissues were assessed immunohistochemically for LC3A, P53. Based on the immunostaining,LC3A expression was separated into high and low groups. The associations of LC3A eexpression with p53expression and with clinicopathological factors, prognosis were sought.Results:1. Immunohistochemical analysis showed that LC3A overexpression was observed in52.7%(128/243) of tumors. Moreover, LC3A mainly localized in the cytoplasm of tumor cells. In contrast to previous reports, LC3A expression was not observed in perinuclear,’stone-like’structures (SLS) in ESCC samples.2. EC3A immunostaining was not linked to clinicopathological factors, such as sex, weight loss, age, tumor location, and, cell differentiation.3. Immunohistochemical analysis showed that p53nuclear overexpression was observed in55.6%(135/243) of tumors. The correlation coefficient between LC3A and p53was-0.0184(P=0.9772)4. The3-year and5-year local control rates were58.2%and47.0%, respectively, in the LC3A lower expression group and46.1%and39.5%, respectively, in the LC3A overexpression group. The difference was not statistically significant(p=0.082).5The survival analysis shows LC3A was not a prognostic marker, while the T stage, N stage, clinical stage, radical surgery and adjuvant therapy correlated with prognosis.6. Of the209patients with stage Ⅱ/Ⅲ(TanyN+M0or T3,4NanyMO),158patients underwent radiotherapy-based therapy after surgery. For this subgroup, Kaplan-Meier curves indicated that the prognosis of the patients with LC3A overexpression was poorer than that of LC3A lower expression(p<0.05). Moreover, in the158patients with adjuvant radiotherapy, the local control rate(LCR) in patients with LC3A overexpression was lower than that with LC3A low expression (p=0.01)。Conclusions:LC3A is expressed in the cytoplasm in ESCC tissues. None of the factors(such as T stage, lymph node metastasis) correlates with LC3A immunostaining. The LCR in patients with LC3A overexpression and adjuvant radiotherapy is lower than that in patients with LC3A low expression and adjuvant radiotherapy. The results above indicate LC3A is a indicator of the sensitivity of concurrent chemoradiotherapy in esophageal squamous cell Carcinoma. Part II:Outcome of concurrent chemoradiotherapy with docetaxel/cisplatin in esophageal squamous cell carcinoma and the predictive significance of LC3A in ESCC sensitivity to concurrent chemoradiotherapy.Objective:Esophageal carcinoma (EC) is one of the most common malignancies worldwide, with poor outcome. In developing countries including China, EC has a higher incidence. There are150,000patients who died of EC, accounting for40%patients in the world. Early EC patients with surgery get good prognosis, while for most patients with advanced EC, the treatment outcome of surgery only is poor, with20%of5-year overall survival rate. Concurrent chemoradiotherapy is the standard treatment modality for nonoperative locally advanced EC patients. For this modality, the5-year overall survival rate of patients with locally advanced EC is30%, and the local relapse is the most common cause. Moreover, the prognosis does not improve by increasing the radiation dose. So finding more efficient chemotherapy regimen is a important way to improve the treatment outcome. Recently, a lot of studies explored the therapeutic effect of the third generation chemotherapeutics in concurrent chemoradiotherapy patterns. Taxanes with platinum has been proven to be an effective regimen, while the the doses and administration methods needs further confirmation. The indicators of tumor biological characteristics are another research hotspot. Although the mechanisms of tumorigenesis and development in ESCC is unknown, a great deal of evidence has shown that the mutation and abnormal expression of cell cycle related, DNA repair related and apoptosis related genes, such as p53,p21,Cyclin D, are involved in the occurrence and development of tumors. In recent years, the role of autophagy in ESCC has attracted more and more attention. Chen et al found that autophagy inhibition improved the radiosensitivity of esophageal squamous cells in vitro. EC3A is an important component in autophagosome. and highly expressed in many types of tumors. The result of part one has shown that ECR in patients with LC3A overexpression and adjuvant radiotherapy was lower than that in patients with LC3A low expression and adjuvant radiotherapy. This demonstrated LC3A was a prognostic factor of radiosensitivity in ESCC. In the following study, the association between LC3A expression and the efficacy of concurrent chemoradiotherapy was explored, and the feasibility of DC chemotherapy combined with radiotherapy was evaluated in patients with ESCC.Materials and methods:Sixty-five patients with ESCC were selected in the Department of Oncology of the Affiliated Hospital of Binzhou Medical College between November2011and Octobor2012.All eligible ESCC patients had the following conditions:diagnosed by endoscopic biopsies; were not suitable or refused operation; KPS greater than80;no contraindication of chemoradiotherapy. The classification of clinical stage was determined according to the Chinese staging criteria for nonoperative esophageal carcinoma. The median age of these patients was62.1years(42～70years).Three-dimensional comformal technique was used in radiotherapy, and the median radiation dose was56.5Gy(44～60Gy). Synchronous chemotherapy was DC(docetaxel20mg/m2and cisplatin25mg/m2,IV dl,8,15,26,33,40).The subjective treatment response was evaluated according to dysphagia remission, and objective response was evaluated according to esophageal barium meal. Toxicities were graded according to the Common Terminology Criteria for Adverse Events v3.0. LC3A protein expression was assessed immunohistochemically. In this study, they were evaluated of the efficacy and the toxicities of the DC regimen combined with radiation and the association between LC3A immunohistochemical expression and the sensitivity toconcurrent chemoradiotherapy in ESCC patients.Results:1.(1) Subjective Response:For ESCC patients with combined therapy of DC chemotherapy and synchronous radiotherapy, dysphagia relief was observed in55of62patients(88.7%).Seven of the55patients with dysphagia relief were able to drink liquid diet before treatment and eat solid without any dysphagia. After treatment, the rate of patients without dysphagia increased from3.1%(2/65)to50.0%(32/64). (2)Objective response:Based on barium meal, the CR rate was48.4%(31/64), PR rate42.2%(27/64), and the objective response rate(ORR)was90.6%(58/64).2. Esophagitis and granulocytopenia were the most frequent acute toxicities in the concurrent chemoradiotherapy. Of the65patients,62/65patients in the study group had esophagitis,and mild esophagitis(grade1/2) was73.9%(48/65), and grade3was21.5%(14/65).With regard to granulocytopenia, it occurred in61.6%(40/65) patients,while only3.1%(2/65) patients had grade3granulocytopenia.3.Based on LC3A expression, the CR rate of the patients with low LC3A expression was58.1%(18/31),while that of the patients with LC3A overexpression was38.2%(13/34).The difference between the two subgroup was statistically significant(p<0.001).Conclusions:The combined treatment modality of DC chemotherapy with synchronous radiotherapy is effective and tolerable in ESCC patients.LC3A is an indicator of the CRT sensitivity.