AIM: To detect aneusomic changes with respect to chromosome 11 copy number in esophageal precancers and cancers wherein the generation of cancer-specific phenotypes is believed to be associated with specific chromosomal aneuploidies. METHODS: We performed fluorescence in situ hybridization (FISH) on esophageal tissue paraffin sections to analyze changes in chromosome 11 copy number using apotome-generated images by optical sectioning microscopy. Sections were prepared from esophageal tumor tissue, tissues showing preneoplastic changes and histologically normal tissues (control) obtained from patients referred to the clinic for endoscopic evaluation. RESULTS: Our results demonstrated that aneusomy was seen in all the cancers and preneoplastic tissues, while none of the controls showed aneusomic cells. There was no increase in aneusomy from precancers to cancers. CONCLUSION: Our results suggest that evaluation of chromosome 11 aneusomy in esophageal tissue using FISH with an appropriate signal capture-analysis system, can be used as an ancillary molecular marker predictive of early neoplastic changes. Future studies can be directed towards the genes on chromosome 11,which may play a role in the neoplastic transformation of esophageal precancerous lesions to cancers. AIM: To detect aneusomic changes with respect to chromosome 11 copy number in esophageal precancers and cancers where the generation of cancer-specific phenotypes is believed to be associated with specific chromosomal aneuploidies. METHODS: We performed fluorescence in situ hybridization (FISH) on esophageal tissue paraffin sections to analyze changes in chromosome 11 copy number using apotome-generated images by optical sectioning microscopy. Sections were prepared from esophageal tumor tissue, tissues showing preneoplastic changes and histologically normal tissues (control) obtained from patients referred to the clinic for endoscopic evaluation. RESULTS: Our results demonstrated that aneusomy was seen in all the cancers and preneoplastic tissues, while none of the controls showed aneusomic cells. There was no increase in aneusomy from precancers to cancers. CONCLUSION: Our results suggest that evaluation of chromosome 11 aneusomy in esophageal tissue using FISH with an appropriate signal capture-analysis system, can be used as an ancillary molecular marker predictive of early neoplastic changes. Future studies can be directed towards the genes on chromosome 11, which may play a role in the neoplastic transformation of esophageal precancerous lesions to cancers.