Relationship between biomarker expression and allelic alteration in esophageal carcinoma

Expression of biomarkers and probable allelic alterations were studied in esophagus tissue samples from patients with esophageal carcinoma.

A total of 116 esophagus tissue samples were obtained from 25 patients with esophagus cancer. Histological studies revealed 23 samples were adenocarcinoma and 14 samples were epidermoid carcinoma while 79 samples were non-tumor. Expression of biomarkers was determined by enzyme immunoassay, and allelic alterations on chromosome 17p were performed by polymerase chain reaction (PCR) using primers D17S513 and D17S514.

The adenocarcinoma group exhibited an increase of matrix metalloproteinase (MMP)-1 (P < 0.0001) and sialyl Le (a) (P < 0.001) mean levels when compared with the non-tumor group. Adenocarcinoma samples from patients with more than three positive lymph nodes had lower levels of tissue-inhibitor metalloproteinase (TIMP)-1 than those with negative nodes (P < 0.0005). Positive allelic alteration was associated with high levels of MMP-1 expression (P = 0.003). Epidermoid carcinoma samples showed higher expression of MMP-1 (P < 0.0001) and TIMP-1 (P < 0.02) than non-tumor samples. Both epidermal growth factor receptor and sialyl Le (a) levels were overexpressed in tumors of patients with more than three positive lymph nodes (P < 0.005). Carcinoembryonic antigen levels were higher in tumors associated with allelic wild type group (P = 0.0001) and patients with negative lymph nodes (P < 0.05). Furthermore, variability in expression of biomarkers was observed according to sample location, and allelic alterations were also found both in tumor and in some non-tumor samples.

The data suggest that overexpression of tissue biomarkers associated with allelic alterations may have potential prognostic implications with different behavior in esophagus cancer.