Mauricio Frías-Mendivil

Bio: Mauricio Frías-Mendivil is an academic researcher. The author has contributed to research in topics: Cancer & Population. The author has an hindex of 7, co-authored 7 publications receiving 377 citations.

Epidemiology of cervical cancer.

Abstract: In 1985, 7.6 million cases of cancer were diagnosed in 24 different regions all over the world (1). Globally, cervical cancer is the fifth most frequent malignancy and second among women, with an annual estimate of 471,000 new cases and 213,000 deaths. The age-adjusted incidence rates for developed countries are 7.6 to 11.8 per 105 and for developing countries, 17.6 to 46.8 per 105 (1,2). This variation in the incidence of cervical cancer is also present within countries, where rural and poor areas have the highest rates.

Epidemiología descriptiva de cáncer en el Instituto Nacional de Cancerología de México

Abstract: Objective. To analyze the descriptive epidemiology of cancer at the Instituto Nacional de Cancerologia of Mexico, and describe the characteristics of the growing demand for medical care. Material and methods. A review of the 10 year experience of the Hospital Cancer Registry from 1985 to 1994 was done. Results. During the study period a total of 28 591 patients was registered with the histological confirmation of cancer. There were 8 984 (31.4%) men, being ,

Human papilloma virus in oral squamous cell carcinoma in a Mexican population

Abstract: Objective To determine the human papilloma virus (HPV) infection in oral cancer and its association with smoking and drinking habits. Study design A cross-sectional study was performed; samples were collected from 51 patients with histological diagnosis of squamous-cell carcinoma were collected at the Instituto Nacional de Cancerologia in Mexico City. HPV infection was detected by polymerase chain reaction, and the clinical characteristics of this population were analyzed. Results Fifty samples out of 51 were positive for β-globin; 21 (42%) cases were HPV-positive, and 14/21 were positive for HPV-16. We found more samples positive in men than in women (71% vs 29%). No differences were observed between HPV-positive and -negative patients in relation to smoking and drinking habits (81% vs 79%). Conclusions HPV infection was present in 42% of patients with oral squamous-cell carcinoma (OSCC); HPV-16 was the most frequent type, identified in 66.6%. Other cofactors participate in the development of OSCC, independent of HPV infection.

Utilidad en la combinación de oligonucleótidos universales para la detección del virus del papiloma humano en cáncer cervicouterino y lesiones premalignas

Abstract: Objective. To determine the prevalence of human papillomavirus (HPV) infection at different stages of the natural history of cervical cancer. Also, to optimize its detection by means of different sets of general primers. Material and Methods. A descriptive, cross-sectional study was conducted between January and December 1999. Samples were processed and analyzed at the Instituto Nacional de Cancerologia (National Cancerology Institute) in Mexico City. A comparative analysis was performed using Student’s t for continuous values and the chi-squared test for proportions. A contingency analysis was made between biopsy and cervical exudates with the Kappa statistic. HPV detection was done by PCR with general primers which recognize different regions of the L1 gene (MY09/11; GP5/6; L1C1/2) and with HPV16- and HPV18- specific primers, as well as direct sequencing of PCR products. Results. In total, 154 samples were analyzed: 65 (42.2%) of them showed normal cytology; 45 (29.2%) high and low grade lesions; and 44 (28.6%) invasive cervical cancer. HPV was detected in 95.5% of invasive cervical cancers, in 91.6% of high grade lesions, in 66.7% of low grade lesions, and in 23.1% of normal smears, by PCR with at least one set of oligonucleotide primers. HPV detection was more efficient in biopsy specimens than in cervical scrapes. The total percentage of HPV detection us

Risk factors for extended-spectrum β-lactamases-producing Escherichia coli urinary tract infections in a tertiary hospital

Abstract: Objective. To assess the risks factors for urinary tract infections (UTIs) caused by Extended-Spectrum Beta-Lactamases (ESBLs)-producing E. coli and the molecular characterization of ESBLs. Materials and methods. A case-control study was performed to identify risk factors in consecutively recruited patients with UTIs caused by ESBLs or non-ESBLs-producing E. coli in a tertiary hospital in Mexico. Results. ESBLs-producing E. coli were isolated from 22/70 (31%) patients with E. coli UTIs over a three month period. All isolates were resistant to cephalosporins and quinolones but susceptible to carbapenems, amikacin and nitrofurantoin. Prior antibiotic treatment with more than two antibiotic families (OR=6.86; 95%CI 1.06-157.70; p=0.028), recurrent symptomatic UTIs (OR=5.60; 95%CI 1.88-17.87; p=0.001) and previous hospitalization (OR=5.06; 95%CI 1.64-17.69; p=0.002) were significant risk factors. Sixteen isolates harbored the beta-lactamase (bla)CTX-M-15 gene and five the blaTEM-1 gene. Conclusions. One of every three patients presented UTIs with ESBLs-producing beta-lactams and fluoroquinolone resistant E. coli. Risk factors and resistance patterns must be taken into account for developing antibiotic use policies in these settings.

Overexpression of p16INK4A as a specific marker for dysplastic and neoplastic epithelial cells of the cervix uteri

Abstract: Cytological screening for cervical cancer or its precursors using Papanicolaou's smear test (Pap test) has been highly efficient to reduce the morbidity and mortality of cervical cancer. However, evaluation of the Pap test relies on subjective diagnostic parameters and is affected by a high rate of false-positive and false-negative results. More objective diagnostic parameters to identify truly dysplastic or neoplastic cells in cervical smears as well as in cervical biopsy samples would therefore avoid insecurity for many patients and the high screening costs associated with repeated testing. Cervical dysplasia is induced by persistent infections through high-risk types of human papillomaviruses (HPVs). Outgrowth of dysplastic lesions is triggered by increasing expression of two viral oncogenes, E6 and E7, which both interact with various cell cycle-regulating proteins. Among these is the retinoblastoma gene product pRB, which is inactivated by E7. pRB inhibits transcription of the cyclin-dependent kinase inhibitor gene p16INK4a. Increasing expression of the viral oncogenes in dysplastic cervical cells might thus be reflected by increased expression of p16INK4a. In line with this hypothesis, we observed marked overexpression of p16INK4a in all cervical intraepithelial neoplasm (CIN) I lesions (n = 47) except those associated with low-risk HPV types (n = 7), all CIN II lesions (n = 32), all CIN III lesions (n = 60) and 58 of 60 invasive cervical cancers. In contrast, no detectable expression of p16INK4a was observed in normal cervical epithelium (n = 42), inflammatory lesions (n = 48) and low-grade cervical lesions (CIN I) associated with low-risk HPV types (n = 7). Dysplastic cells could also be identified in cervical smears using a specific p16INK4a monoclonal antibody. These data demonstrate that p16INK4a is a specific biomarker to identify dysplastic cervical epithelia in sections of cervical biopsy samples or cervical smears. © 2001 Wiley-Liss, Inc.

Mathematical Model for the Natural History of Human Papillomavirus Infection and Cervical Carcinogenesis

Abstract: The authors constructed a Markov model as part of a systematic review of cervical cytology conducted at the Duke University Evidence-based Practice Center (Durham, North Carolina) between October 1997 and September 1998. The model incorporated states for human papillomavirus infection (HPV), low- and high-grade squamous intraepithelial lesions, and cervical cancer stages I-IV to simulate the natural history of HPV infection in a cohort of women from ages 15 to 85 years. The age-specific incidence rate of HPV, and regression and progression rates of HPV and squamous intraepithelial lesions, were obtained from the literature. The effects of varying natural history parameters on cervical cancer incidence were evaluated by using sensitivity analysis. The base-case model resulted in a lifetime cervical cancer risk of 3.67% and a lifetime cervical cancer mortality risk of 1.26%, with a peak incidence of 81/100,000 at age 50 years. Age-specific distributions of precursors were similar to reported data. Lifetime risk of cancer was most sensitive to the incidence of HPV and the probability of rapid HPV progression to high-grade lesions (two- to threefold variations in risk). The model approximates the age-specific incidence of cervical cancer and provides a tool for evaluating the natural history of HPV infection and cervical cancer carcinogenesis as well as the effectiveness and cost-effectiveness of primary and secondary prevention strategies.

Cancer Screening in the United States, 2007: A Review of Current Guidelines, Practices, and Prospects

Abstract: Each year, the American Cancer Society (ACS) publishes a summary of its recommendations for early cancer detection, including guideline updates, emerging issues that are relevant to screening for cancer, and a summary of the most current data on cancer screening rates for US adults. In 2006, there were no updates to ACS guidelines for early cancer detection. In this issue of the journal, we describe criteria for successful screening, discuss recent evidence and policy changes that have implications for cancer screening, summarize the ACS guidelines and describe guidelines reviews that are underway, and provide an update of the most recent data pertaining to participation rates in cancer screening from the Centers for Disease Control and Prevention's (CDC's) Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS).