Role of Immunohistochemistry Markers (p53 and CEA), in Study of Colorectal Tumours

Colorectal cancer is the third most common cancer in men and the second in women globally. There is a marked variation in the incidence of colorectal carcinoma worldwide, where western countries having high rate compared to others. p53 tumour suppressor gene is one of the most intensively studied tumour markers in the colorectal tumours. Two markers were used, p53 (oncoprotein p53) and CEA (carcinoembryonic antigen) in the study. The 102 cases of paraffin-embedded samples were processed for the immunohistochemistry examination. After the analysis of the selected patients regarding the antibodies distribution, statistical analysis was performed. The current study showed that there was a statistically significant correlation existing between p53 and CEA in each tumour type irrespective of its histological grades. The immunohistochemistry (IHC) was performed on 4-µm thick sections from 10% formalin- fixed paraffin-embedded tissue blocks.

Cancers

With more than half of all cancer cases occurring in less developed nations of the world, cancer is a source of significant and growing mortality worldwide, with an increase to 19.3 million new cancer cases per year projected for 2025. Standard current treatments for cancer include surgery, radiotherapy, and a host of other systemic treatments comprising cytotoxic chemotherapy, hormonal therapy, immunotherapy, and targeted therapies. Referred to as the “guardian of the genome,” the alteration or inactivation of p53 tumour-suppressor gene by mutation or by its interactions with oncogene products or DNA tumour viruses can lead to cancer. The p53 is mutated in about half of almost all types of cancer arising from a wide spectrum of tissues. This chapter focuses on several types of cancer including breast and ovarian, colorectal, small cell lung carcinoma, malignant melanoma, pancreatic, prostate, neurofibromatosis, multiple endocrine neoplasia, and retinoblastoma.

Antimutagenic Efficacy of Some Natural Compounds on Cyclophosphamide-Induced p53 Alterations

Mutations in the p53 tumour suppressor gene have been associated with chemical carcinogens. Natural antimutagens are promising modulators for reducing the cancer risk. The present study was carried out to assess the protective efficacy of some natural antimutagens against p53 alterations. We investigated the ability of curcumin (100 mg/kg BW) and chlorophyllin (3 mg/kg BW) pretreatment, for three times per week for three successive weeks, to inhibit mutations induced by intraperitoneal injection of a single dose of 40 mg/kg BW of cyclophosphamide (CP). Forty male albino rats were assigned into four groups: control nontreated group, CP-treated group, curcumin-CP-treated group, and chlorophyllin-CP-treated group. Liver samples were collected for DNA isolation two days after CP injection. The isolated DNA was used in single-strand conformational polymorphism (SSCP) analysis of polymerase chain reaction (PCR)-amplified products of four regions: two in exon 5, one in exon 6, and one in exon 7. The amplified products of p53 different regions were found to be in the expected molecular size of the designed primers. SSCP analysis of these amplified products showed that CP-induced mutation in the p53 gene was found only in exon 7 shifting its electrophoretic mobility. Chlorophyllin treatment prior to CP injection had a more potent protective efficacy (80%) than that with curcumin (33.3%).