Association of upregulated GATA-4 transcription factor colorectal adenocarcinoma with metastatic and primary tumors
e15093 Background: GATA-4 zinc finger transcription factor is involved in regulation of cellular development, proliferation, and differentiation and is important in embryonic development of gastrointestinal tract. However, GATA-4 is not expressed in normal adult colonic mucosa. Its protein expression in colonic adenocarcinoma has not been systematically evaluated and small number of samples was previously reported as negative. Nuclear factor-B (NF-B) activation was shown to promote the growth of the colon tumors in experimental models and was correlated with tumor angiogenesis and progression in human colorectal cancer. Methods: Forty cases of colorectal adenocarcinoma were evaluated. The benign colonic mucosa and the matching metastatic tumors of the same patients were also included in the study. TMAs which included 139 samples were evaluated by immunohistochemistry and nuclear and cytoplasmic GATA-4 expression was scored (0–3+). NF-B activation was detected as nuclear reactivity for p65. Results: GATA-4 was expressed in 32% of colorectal adenocarcinoma, but not in benign colonic mucosa (p=0.0001, Chi-Square). GATA-4 was also significantly more expressed in metastatic (41%) than in primary (21%) colorectal adenocarcinoma (p<0.0001, Chi-Square). NF-B activation was not present in any of the samples of benign colonic mucosa, but it was detected in 64% adenocarcinomas (p<0.0001, Chi-Square). While there was no difference in NF-B activation between primary vs. metastatic adenocarcinoma, a strong positive association between GATA-4 expression and NF-B activation (p<0.0001, Linear-by- Linear) was found. Conclusions: GATA-4, a developmental transcription factor is not expressed by normal colonic mucosa, but is present in 1/5 of primary tumors that gave rise to distant metastases and in almost 1/2 of their respective metastases. GATA- 4 is also strongly positively associated with NF-B activation previously described to have a role in human cancer progression. GATA-4 may have a role in colorectal adenocarcinoma development and progression and it should be further evaluated in prospective studies as a putative adverse prognostic factor in colorectal adenocarcinoma. No significant financial relationships to disclose.