The influence of vitamin D and receptor status in colorectal cancer.

Abstract

435 Background: Since vitamin D is a modifiable factor, we have proposed to evaluate vitamin D levels and cognate receptor expression in patients presenting with colorectal cancer (CRC). Previously, we retrospectively assessed vitamin D receptor (VDR) level in 98 CRC tumor tissues and noted a variation of expression with tumor stage (GI ASCO 2009 abs # 371). Methods: We prospectively evaluated 38 cases of CRCs newly diagnosed during 3 consecutive summers and assessed demographics, pathological characteristics and long-term clinical outcomes. Skin color was determined by the Fitzpatrick photo typing scale. At the time of enrollment, vitamin D levels were assessed, and a twenty point lifestyle assessment questionnaire was administered. Descriptive statistics were performed. Tumor and corresponding normal tissues are being evaluated to identify the patterns of VDR expression and expression of the Wnt/B-catenin inhibitors-Dickkopft 1(DKK-1) and Dickkoft-4 (DKK-4), which have been implicated in development of CRCs. Results: 38 patients diagnosed with CRC 24 were men and 14 were women with median age at diagnosis was 59 yrs (range, 28-78 yrs). Median follow up after diagnosis was 2.1 yrs (range, 0.06, 3.68 yrs). Histological grades of adenocarcinomas were well differentiated as well (13%), moderately differentiated (66%), and poorly differentiated (7%), and mucinous types (11%). Patients were staged as I (8%), II (39%), III (34%), or IV (19%). 81% of patients were treated with chemotherapy in an adjuvant or neo-adjuvant setting. The median serum total 25-hydroxy vitamin D level was 23 ng/ml (range, 6-87 ng/ml). There was no substantial difference in median vitamin D levels between lower and higher stages (25 vs 21). Lower stages of CRC were associated with lighter skin types (Fitzpatrick scale types I and II) and advanced stages with darker skin types (IV-VI); this could be a reflection of variable VDR expression. Conclusions: We are analyzing VDR expression as a covariate to compare to vitamin D levels, skin color, and stage. Results will be reported at the time of presentation. These studies were supported by a pilot project grant by the UAB Comprehensive Cancer center.