Aim of study: Colorectal cancer (CRC) is the fourth most prevalent cancer globally. Several factors have roles in cancer establishment. One of the most important factors is hypoxia that induces hypoxia inducible factor-1 (HIF-1). The HIF-1 alpha overexpressed in hypoxia conditions and plays a pivotal role in carcinogenesis features. In this study, we aimed to examine the efficiency of HIF-1 alpha gene expression at mRNA and protein's level for CRC diagnosing and staging.
Materials and methods: In this study, the cases included into 75 cancer specimens in different stages (Group 2 = Stage 1, Group 3 = Stage 2, and Group 4 = Stage 3, 4) and ten normal specimens as control (Group 1). Real-time reverse transcription-polymerase chain reaction and immunohistochemistry (IHC) were performed for measuring gene expression at RNA and protein's level, respectively. The raw data were analyzed in the SPSS20 software.
Results: HIF-1 alpha gene expression rate (2-ΔΔCT) and ΔCT values were significantly higher increased in Group 4 in compare to control (P < 0.001). Other cancer groups (2 and 3) had greater ΔCT values than control, but it was not statistically significant. Moreover, the rate of HIF-1 alpha gene expression (2-ΔΔCT) was increased with cancer stages. According to the IHC results, there was a positive relationship between CRC stages and HIF-1 alpha protein expression (P < 0.05).
Conclusions: HIF-1 alpha gene expression increased in earlier up to metastasis stages of CRC, but the assessment of HIF-1 alpha gene expression has not important role in the diagnosis of cancer in early stages and classification of carcinoma because the increasing of HIF-1 alpha gene expression is not significant in early cancer stages.