Molecular analysis in combination with iodine staining may contribute to the risk prediction of esophageal squamous cell carcinoma

Abstract

Purpose: Mucosal iodine staining has improved the detection of precancerous lesions of the esophagus. However, this method is unable to exactly evaluate the risk status of the lesions. In the present study, we conducted a molecular analysis combining the iodine staining in esophageal squamous cell carcinomas (ESCC) and different premalignant lesions of the esophagus in order to improve the early diagnosis of ESCC.

Methods: Tumorous and precancerous lesions were procured as iodine-unstained areas in the resected specimens of ESCC patients by means of Lugol's iodine staining. Loss of heterozygosity (LOH) was detected with 35 microsatellite markers frequently reported to be deleted in ESCC. The markers with high frequency of LOH in tumorous and precancerous lesions of the same patient were subjected to further detection in iodine-unstained biopsy samples from the population screening in ESCC high-incidence region.

Results: Common alterations were observed at D3S3644, D3S1768, D3S3040, D3S4542, RPL14, D9S169, D13S171 and D13S263 in both cancer tissues and precancerous lesions around tumors. Interestingly, D3S3644, D3S1768, D3S3040, D3S4542, RPL14 and D13S263 were also found with high frequency of LOH in iodine-staining abnormal lesions from the population screening. Most importantly, LOH frequency increased with histological severity.

Conclusion: Our data suggest that detection of these six markers in combination with iodine staining might contribute to the prediction for the risk of ESCC development and for the diagnosis of patients in preclinical and preneoplastic phase of the disease.

Fig. 1

a Iodine-unstained areas before taking samples from resected specimen. b Iodine-unstained areas after taking samples from resected specimen. c Position of biopsy under the endoscope from population screening in the ESCC high-incidence region. open arrows tumor tissues; filled arrows iodine-unstained areas; arrows normally iodine-stained areas

Fig. 2

Cases with different LOH patterns. a LOH of D3S3040 in case S25, loss of the lower allele in U1, U2 and T. b LOH of D3S3040 in case S30, loss of the lower allele in U1. c LOH of D3S3040 in case S21, showing loss of the lower allele in U1, U3 and T. Note, U1 is histopathologically normal iodine-unstained tissue. d LOH of D3S3040 in case S29, D3S3040 showing loss of the lower allele in U1 and T, whereas U2 with loss of the upper allele. B blood DNA; N normally iodine-stained mucosa; U iodine-unstained mucosa. T tumor tissue

Fig. 3

LOH in biopsy samples. C normally iodine-stained mucosa, U iodine-unstained mucosa