Antibody detection against HPV16 E7 & GP96 fragments as biomarkers in cervical cancer patients.

Background & objectives: Cervical cancer is the second most frequent cancer among females worldwide, especially human papilloma viruses (HPV) types 16 and 18. In viral systems the identification of serological markers would facilitate the diagnosis of HPV infections and virus-related disease. The aim of the present investigation was to determine and search for serologic markers in cervical cancer patients associated with HPV. Methods: A total of 58 Iranian women with invasive cervical carcinoma including adenocarcinoma and squamous cell carcinoma (SCC) were included. Serum antibody response to HPV infections in patients was detected by Western blot and ELISA techniques based on recombinant HPV16E7 and the N-terminal and C-terminal fragments of gp96 (NT-gp96 and CT-gp96) proteins. These recombinant proteins were expressed in Escherichia coli as a His-tag protein and purified using affinity chromatography. Results: The ELISA results indicated that patients with high antibody response to HPV16E7 had significant seroreactivity to CT-gp96 fragment. In Western blot analysis, a strong association between anti-E7, anti-NT-gp96 and anti-CT-gp96 reactivity and cervical cancer was obtained using purified recombinant proteins. In adenocarcinoma cases, no significant difference was observed in seroreactivities between normal and patients. Interpretation & conclusions: The evaluation of cervical cancer patients' seroreactivities against three recombinant proteins (rE7, rNT-gp96 and rCT-gp96) showed significantly higher levels of these markers in SCC only, but not in adenocarcinoma and control groups. Also, the usage of both techniques (ELISA and Western blotting) can provide more reliable tools for diagnosis of cervical cancer.

Anti-P53 antibodies in Brazilian brain tumor patients

Gliomas of astrocytic origin are the most common primary brain tumors, accounting for over 40 to 50 of all central nervous system tumors. The TP53 tumor suppressor gene is the most frequently mutated gene found in human malignancies. A mutation of this gene can lead to an increased half-life of the resulting protein and loss of biological function. High levels of p53 have been detected in the serum of colon cancer patients, although p53 protein has not been detected in the serum of brain tumor patients. Besides circulating p53, several studies have detected antibodies against p53 in patients with lung and breast cancer, as well as those with other types of cancer. We studied p53 protein and anti-p53 antibodies in the plasma of Brazilian brain tumor patients. Plasma samples were drawn from 24 untreated brain tumor patients and from 15 healthy donors without clinical signs of cancer. Western blotting techniques were used to detect p53 protein and anti-p53 antibodies. We found anti-p53 antibodies in 5/24 brain tumor patients. Age appears to affect the immune response, as four of six tumor patients under 16 years old had detectable anti-p53 antibodies, while these were found in only 1 of 18 adults (over 16 years old). We found no p53 protein in any of the serum samples from the brain tumors. Possibly the presence of this protein is affected by tumor type or by the organs that are sampled

Clinical associations and prognostic significance of serum anti-p53 antibodies in Thai patients with hepatocellular carcinoma.

Mutations of the p53 gene have been reported to be of prognostic significance in hepatocellular carcinoma (HCC). However, the clinical associations and prognostic value of anti-p53 antibodies, known to be products of the host immune response to these mutations, have been controversial. Serum anti-p53 antibodies were measured in 121 Thai patients diagnosed with HCC using a specific enzyme-linked immunosorbent assay (ELISA) kit. The clinical/pathological characteristics of the patients were compared with respect to the presence of serum anti-p53 antibodies. Cox regression analysis was performed to assess factor interaction and association with survival. Anti-p53 antibodies were detected in 13.2% (16 of 121) of our patients. There were no differences between groups with regard to age, sex, viral markers (HBsAg or anti-HCV), severity of liver disease and tumor advancement. The median survival rates for patients positive and negative for anti-p53 antibodies were 4.0 and 3.0 months, respectively (p = 0.443, by log-rank test). Multivariate analysis demonstrated that an advanced Okuda stage, lack of therapy and presence of portal vein thrombosis were independent factors related to the prognosis of the patients. Nonetheless, the presence of anti-p53 antibodies did not constitute a predictive variable associated with a poorer prognosis. Serum assay of anti-p53 antibodies, although rapid and easily performed, may not be suitable as an alternative to molecular detection of mutations in assessing tumor advancement and prognosis of patients with HCC.

Prevalence and clinical relevance of serum anti-p53 antibodies in patients with cholangiocarcinoma.

Cholangiocarcinoma (CCA) constitutes carcinoma of the bile duct found at a high prevalence in northeastern Thailand. In the present study, we examined the sera of altogether 82 Thai CCA patients for the presence of anti-p53 antibodies in order to investigate a role of the tumor suppressor gene, p53 in the carcinogenesis. Our results revealed anti-p53 antibodies in 7.3% of the cases tested, which conforms to the prevalence rate of p53 gene mutation recently reported at 5% among Thai patients. With limited number of the patients, anti-p53 antibodies were rapidly detected more frequently among patients with peripheral tumors than those with central tumors. However, further studies is required to establish significance and prognostic value of the antibodies in the context of CCA.

Prevalence of serum antibodies to LA-1 oncoprotein, herpes simplex virus type-2 glycoprotein and human papillomavirus type 16 transactivator (E2) protein among Indian women with cervical neoplasia.

Prevalence of serum antibodies to synthetic peptide to oncoprotein of LA-1 known as oncogene of herpes simplex virus type-2, herpes simplex virus type-2 glycoprotein-D as an determinant of viral pathogenicity and human papillomavirus type 16 transactivator E2 protein was studied among 46 Indian women with cervical neoplasia using immunoblot assay for HSV-2 gD glycoprotein and LA-1 antibodies as well as peptide ELISA assay to detect HPV16 E2 antibodies. The seropositivity to LA-1 oncoprotein was found to be high (61%) among patients with invasive cervical carcinoma as compared to 35% in various grades of cervical intraepithelial neoplasia (CIN) and 36% in normal control women. In contrast to this, a uniformly high frequency of antibody to HPV 16 E2 was observed among women with CIN (68%), normal healthy controls (50%) and invasive cervical carcinoma (43%). However, a low frequency of seropositivity (13%) to recombinant vaccinia virus HSV-2 gD protein was found among 15 tested sera each from group of women with various grades of CIN as well as invasive cervical carcinoma as compared to 28% among seven normal healthy control. A negative correlation of LA-1 and HPV16 E2 seropositivity on patient by patient comparison among CIN and invasive cervical carcinoma group was observed which is statistically significant (P = 0.019 for CIN; P = 0.038 for invasive cervical carcinoma). However, a positive correlation (P = 0.144) was found among normal control women. The study has shown a desirable serological marker of cervical neoplasia. This serological marker could be employed as a screening tool in conjunction with cytopathological screening to diagnose women harbouring LA-1 oncogene associated cervical lesions.

Detection of antibodies to human melanoma cell in vitiligo by western blot analysis

Vitiligo is a disease in which melanocytes are selectively destroyed. The disease is thought to be an autoimmune process being there are antibodies to pigment cells in the sera of patients and animals with vitiligo. In the present study, sera from vitiligo patients were examined for reactivity with the human melanoma cell line, SK-Mel-28, by Western blot analysis of solubilized membrane antigens of these cells to identify the pigment cell antigens defined by antibodies in the patients with vitiligo. Antibody reactivity to human melanoma cells (SK-Mel-28) was investigated in 14 patients with vitiligo, and 16 with normal control individuals. Antibodies to the 116-113, 60, 40 KD antigens were associated with vitiligo being present in 79%, 86%, and 43% respectively of the patients with vitiligo, but in only 6%, 38% and 6% of the normal controls. In contrast, antibodies to the 160-155, 78 and 64 KD antigens were equally common in vitiligo and in normal individuals. The results suggest that autoreactivity to pigment cells occurs more commonly in patients with vitiligo than in the normal control and high autoreactivity to pigment cells in the vitiligo sera might be an impertinent epiphemenon to destroyed pigment cell.