Interpretation of P16 expression as a marker of HPV in colorectal cancer.

BACKGROUND: Colorectal cancer is one of the most prevalent types of tumors worldwide. P16ᴵᴺᴷ4ᵃ is a widely used immunohistochemical marker for high-risk HPV infection. The purpose of this study is to explore the relationship between P16 expression as an indicator of HPV infection and colorectal cancer in Egyptian patients, as well as its association with histopathological characteristics. MATERIAL AND METHODS: The study was performed on 59 cases of colorectal carcinoma cases and 30 specimens of normal colonic mucosa. RESULTS: p16 protein was detected in 22% (13 of 59) of patients with colorectal carcinoma. No evidence of P16 expression in all 30 cases of non-neoplastic colonic mucosa was found. More frequent expression of P16 was seen in distal carcinomas. CONCLUSION: our study demonstrated that P16 protein is expressed in a reasonable percent of colorectal carcinoma cases, suggesting a role of HPV in colorectal carcinogenesis. The present study highlights the role of p16 protein expression which is important in the pathogenesis in colorectal carcinoma, especially regarding distal tumors.

Natural killer NKG2A and NKG2D in patients with colorectal cancer.

BACKGROUND: Natural-killer group 2 (NKG2), a characteristic receptor of natural killer (NK) cell family, assumes a vital role in modulating NK cytotoxic function. We aimed to detect mRNA expression of both NKG2A and NKG2D in serum NK cells obtained from colorectal cancer (CRC) patients. METHODS: We enrolled 36 patients with newly diagnosed CRC, as well as 15 group matched healthy individuals. The patients were further classified into: 23 non-metastatic CRC (group 1) and 13 metastatic CRC (group 2). We detected the expression of NKG2A and NKG2D serum levels for all participants utilizing real-time polymerase chain reaction (RT-PCR). RESULTS: NKG2D and NKG2A mRNA levels in peripheral blood mononuclear cells (PBMCs) were significantly elevated in patients with CRC compared to controls (P<0.01). NKG2D or NKG2A showed sensitivity (77.8, 83.33%) and specificity (73.33, 100%) respectively using receiver-operating characteristic (ROC) curve analysis for discrimination between patients and controls, whereas group 1 and group 2 showed no statistical significant difference in NKG2D and NKG2A levels (P>0.05). CONCLUSIONS: Our work is one of the first research that could detect an increase in NKG2D in CRC. In spite of their defensive role in tumor immune surveillance, NKG2D and NKG2A and their ligands could have misused as tumor survival tool, empowering immune avoidance and suppression.