Genetic analysis of H-ras intron-1 polymorphic and variable tandem repeat regions in human breast cancer.

H-ras is a member of the ras superfamily of genes. This gene encodes for a 21 kDa protein (p21) which is located on the inner surface of the plasma membrane. Ras genes are involved in a wide variety of human tumors, and there is a known correlation between H-ras activation and breast carcinogenesis. H-ras contains a polymorphic region, a repeated hexanucleotide -GGGCCT - located in intron 1 close to the 5' of the gene (HRM region). Three alleles of this region, P1, P2 and P3, have been identified that contain two, three and four repeats of the hexanucleotide, respectively. H-ras possesses a minisatellite DNA of the variable tandem repeat (VTR) which is located 1000 bp downstream of the gene displaying linkage disequilibrium with HRM. The purpose of this study was to estimate the frequency of P1, P2 and P3 in the normal population and in patients with breast cancer. We studied 56 biopsy specimens from patients with breast cancer, 61 normal blood samples, and 30 pairs of normal and tumoral breast tissues for VTR analysis. There was a difference in the distribution of P1, P2 and P3 alleles between normal and breast cancer samples. The frequency of P1 homozygosity was shown to be almost twice as high in women with breast cancer compared to healthy women (72% versus 39%). These results suggest that P1 homozygosity may be considered as a potential risk factor in breast carcinogenesis. In VTR analysis one sample presented a shift in mobility, but no polymorphism in the BstN I pattern of the 28 bp repetition core was observed.

In vivo detection of human papilloma virus-induced lesions of anogenital area after application of acetic acid: a novel and accurate approach to a trivial method.

Human papilloma virus infection is increasing at an alarming rate. The ability of the virus to establish a subclinical infection and its association with malignancy of the lower genital tract make the statistics even more worrisome. Topical application of acetic acid solution provokes temporal alterations of the light-scattering properties of human papilloma virus-induced lesions of anogenital area. For the in vivo study of the phenomenon, an imaging system has been employed, which performs time-lapse imaging and enables the calculation and display of the kinetics of the provoked alterations in any point within the examined area. Confirmation of diagnosis has been established with conventional histology and polymerase chain reaction. It has been shown that the method provides early detection and staging of skin alteration or transformation due to human papilloma virus infection and enables mapping of the infected area.

Human papillomavirus infection of non-melanoma skin cancers in immunocompetent hosts.

Human papilloma viruses (HPVs) consist of more than 70 different types and are known to be associated with numerous malignant tumors, including carcinomas of the mucosal and cutaneous epithelium. Non-melanoma skin carcinoma (NMSC) is the most frequently occurring malignancy worldwide in the Caucasian population. Most studies examining the involvement of papillomaviruses in the development of cutaneous carcinomas have been performed on lesions from patients with epidermodysplasia verruciformis or from immunosuppressed patients. Our specimens were obtained from 108 immunocompetent patients with benign and malignant skin lesions, and HPVs were detected in 27%. HPV 8 and HPV 18 were the most frequent types (62 and 48%, respectively). Our results suggest that HPVs, particularly the oncogenic potential of certain types such as HPV 8, 18, and 5 could contribute to the development of NMSCs.

p53 codon 72 polymorphism as a risk factor in the development of breast cancer.

The p53 gene is polymorphic at amino acid 72 of the protein that it encodes. It has been reported that patients with the arginine form have a higher risk of developing other forms of cancer than those with the proline form. The purpose of this study was to examine whether p53 Arg at the polymorphic position 72 could represent a risk factor for women with breast lesions. The study population included 56 biopsies from patients with breast lesions. Also, 61 normal blood samples were used as controls. There was a difference in the distribution of p53 genotypes between breast cancer lesions and the normal samples. The allele frequency of p53 Arg/Arg was much higher than that of the normal samples (61% versus 20%). Based on the findings of this study, it is suggested that p53 Arg homozygosity could represent a risk factor for the tumorigenesis of the breast.

Molecular basis of gynecological cancer.

Alterations in the cellular genome affecting the expression or function of genes controlling cell growth and differentiation are considered to be the main cause of cancer. Genes that cause cancer are of two distinct types: oncogenes and onco-suppressor genes. The normal proto-oncogene can be converted into an active oncogene by deletion or point mutation in its coding sequence, gene amplification, and by specific chromosome rearrangements. Mutations and abnormal expression in ras, myc, c-erbB-2, and other oncogenes have been reported in several types of gynecological cancer. Onco-suppressor genes are involved in gynecological cancer, their functions are localized in different phases of the cell cycle. Structural changes and deletions of these genes can cause cancer. Mutations in the p53, BRCA1, DCC, and PTEN genes have been reported in gynecological cancers such as ovarian, cervical, and endometrial cancer. Human papillomaviruses are of major interest because specific types (HPV-16, -18, and several others) have been identified as causative agents in at least 90% of cancers of the cervix. In this study we summarize the available information regarding the implication of specific oncogenes, onco-suppressor genes, and HPV in the development of female genital malignancies.

P53 codon 72 polymorphism as a risk factor in the development of HPV-associated cervical cancer.

Human papilloma virus (HPV) has been implicated in cervical carcinoma, and the p53 gene is polymorphic at amino acid 72 of the protein that it encodes. The association between p53 polymorphisms and risk for HPV-associated cervical cancer has been examined, but the results have been conflicting. It has been reported that patients with the arginine form have a higher risk of developing cervical cancer than those with the proline form. The purpose of this study was to examine whether p53 Arg at the polymorphic position 72 could represent a risk factor for women with high-risk HPV-associated premalignant and malignant cervical lesions. The study was carried out on 60 smears from patients with high-risk HPV-related cervical lesions. Also, 74 HPV-negative normal smears and 61 normal blood samples were used as controls. HPV-18 was the most frequent type. There was a difference in the distribution of p53 genotypes between high-risk HPV-cervical lesions and the normal samples. The allele frequency of p53 Arg/Arg was much higher than the normal samples (46.5% versus 20.5% in HPV-negative normal smears and 20% in blood samples). Based on the findings of this study, it is suggested that p53 Arg homozygosity could possibly represent a potential risk factor for the tumorigenesis of the cervix. Statistically significant correlation was not observed between the presence of Arg/Pro homozygosity or Arg/Pro heterozygosity and HPV typing.

P53 codon 72 polymorphism as a risk factor in the development of HPV-associated non-melanoma skin cancers in immunocompetent hosts.

Human papilloma virus (HPV) has been implicated in skin cancer. Also, in human populations, the p53 gene is polymorphic at amino acid 72 of the protein that it encodes. The association between p53 polymorphisms and HPV-associated skin cancer risk has been examined, but the results were conflicting. It was revealed that the arginine form of p53 is more susceptible to degradation by the HPV E6 protein than the proline form and that patients with the arginine form have a higher risk of developing cancer than those with the proline form. The purpose of this study was to examine whether p53 Arg at the polymorphic position 72 could represent a risk factor for patients with high risk HPV-associated malignant skin lesions. The study was conducted on 29 high risk HPV-related skin lesions from Greece. Blood samples from 61 healthy individuals were used as controls. HPV-8 was the most frequent type. There was a difference in the distribution of p53 genotypes between high risk HPV-skin lesions and the controls, and the allele frequency of p53 Arg/Arg was much higher than the controls (65.5% versus 20%). Therefore, it is suggested that p53 Arg homozygosity could represent a potential risk factor for tumorigenesis of the skin.

Ras gene activation in malignant cells of human ovarian carcinoma peritoneal fluids.

In this study, we showed, for the first time, the pattern of point mutations at codon 12 of the K-ras, H-ras and N-ras genes, using polymerase chain reaction and restriction fragment length polymorphism analysis in 47 malignant cytologic specimens of ovarian adenocarcinoma peritoneal fluids. Forty-seven % of the samples were found to carry a point mutation at codon 12 of K-ras gene. Also, 21 cystadenoma peritoneal fluids were used as control specimens for the detection of ras mutations. Fourteen % of these samples were found to carry a point mutation at codon 12 of the K-ras gene. The prevalence of K-ras gene mutations were statistically correlated with FIGO and surgical stage of the malignant specimens. Our data demonstrates that the K-ras gene mutations are mainly affected (47%) in the malignant cells of the peritoneal washings or ascites of women with ovarian adenocarcinomas and may have value for the early diagnosis and monitoring of these neoplasms.

High prevalence of HPV18 in correlation with ras gene mutations and clinicopathological parameters in cervical cancer studied from stained cytological smears.

The multi-event nature of carcinogenesis has led to extensive studies of oncogenes, onco-suppressor genes and viruses involved in human cancers. The collaboration of ras oncogene with HPV E6/E7 genes inducing full transformation of cervical keratinocytes has also been suggested. The purpose of this study was to detect the presence of codon 12 point mutations of ras genes, as well as to detect and identify the human papillomaviruses in stained smears of cervical malignancies and to correlate them with the clinicopathological parameters of the Greek patients. Specimens were obtained from 88 women, codon 12 point mutations of the K-ras (30%) and H-ras (10%) oncogenes, as well as HPV18 were detected at a higher rate than HPV16 (66% vs 7%) in cervical lesions by PCR-RFLP and PCR analysis, respectively. The statistical analysis of the data demonstrates correlation between the presence of K-ras mutations and FIGO stage and between FIGO stage and survival of the patients. It is suggested that ras activation combined with HPV infection may be an important step in the carcinogenesis of a substantial number of cervical carcinomas.

Detection of HPV and ras gene mutations in cervical smears from female genital lesions.

The collaboration of ras oncogenes with HPV E6/E7 genes inducing full transformation of cervical keratinocytes has been suggested. The purpose of this study was to detect and type HPV by PCR and to assess the extent of involvement of the ras oncogene activation by point mutations in cervical premalignant and malignant lesions, using stained PAP cervical smears. Specimens were obtained from 35 women with genital lesions, and codon 12 point mutations of the K-ras and H-ras oncogenes were detected, as well as HPV18 at a higher rate than HPV16 (48% vs 10%) in cervical lesions by PCR-RFLP and PCR analysis, respectively. Our study indicates that the mutational activation of the K-ras gene may be involved in the development of a small subset of cervical carcinomas and that mutationally activated ras oncogenes cooperate with HPV in the early stages of carcinogenesis in the cervix of the uterus.