Oral manifestations as a hallmark of malignant acanthosis nigricans

We present a case of malignant acanthosis nigricans (AN) that initially manifested in the oral cavity. In the present report, the patient had typical clinical and histological findings of oral and esophageal AN, with subtle skin changes, associated with a gallbladder adenocarcinoma. The importance of the clinical oral examination is emphasized because the recognition of oral lesions led to the diagnosis of AN and to the following detection of the internal malignancy. Since the tumours associated with AN are highly malignant, it is of the utmost importance to recognize the skin and mucous membrane changes in adults.

Human papilloma virus 16-18 infection and cervical cancer in Mexico: a case-control study

Cervical cancer (CC) is one of the principal public health problems in Mexico. The national mortality rate due to CC was estimated at 21.8 per 100,000 among women over 15 years old during 1994. Despite this high incidence little is known in Mexico about the risk factors for CC. The objectives of the study were to evaluate the association between CC and HPV types 16 and 18 in women living in Mexico City. From August, 1990 to December, 1992, a case-control study was carried out in the metropolitan area of Mexico City. HPV 16-18 types were determined in a sample of 148 CC cases and 204 controls randomly selected from a sample frame representative of the metropolitan area of Mexico City. Sixty cases corresponded to in situ CC and 88 cases to the invasive phase. Determination of HPV 16 and 18 types was done by polymerase chain reaction using primers specific to E6/E7. Results showed that 48.3% of in situ CC cases and 48.8% of invasive CC cases were positive for HPV 16 while only 13.2% were positive among the 204 controls. Association between HPV 16 infection in the in situ cancer cases had an estimated odds ratio (OR) of 5.17 (95% CI 2.60-10.51). In the invasive cervical cancer cases, association between HPV 16 infection and invasive CC in this sample had an OR of 3.84 (95% CI 2.04-7.22). For the total sample, the estimated OR was 5.48 (95% CI 3.07-9.62). In the total sample, those women with a strong positive reaction to PCR were associated with a large increase in the risk, OR of 38.0 (95% CI 8.66-167.1). The prevalence the HPV 18 was 6.7%, only observed in the invasive cervical cancer cases. At present there is general consensus that HPV is the principal causal agent in C C etiology. This study intends to contribute to the knowledge concerning the etiology of cervical cancer. However, it is necessary to consider that the single most effective tool in the reduction of mortality due to cervical cancer has been the Pap test. Secondary prevention has proven to be highly effective in other populations, and this should be viewed as a priority activity for all at-risk populations. Although a vaccine for HPV may be available in the near future its efficacy in primary prevention has yet to be demonstrated.

[Genetic diversity of 3 DNA probes in the DNA fingerprinting of a Mexican population]

Each individual may be identified by characterizing its genetic material by DNA fingerprinting technology. Its application in Mexico demands a knowledge of the allelic and genotypic diversity of the DNA markers and the probability that two individuals may have the same fingerprint. In the present study the allelic and genotypic diversities of the loci D12S11 (MS43A), D7S22 (g3) and D1S7 (MS1) were determined in 100 Mexican students of the military school of medicine (Escuela Médico Militar de México). The mean allelic frequency of the loci MS43A, g3, and MS1 was 0.01, 0.008 and 0.006, respectively. The heterozygosity of MS43A and g3 was 98 and 99% for MS1. The probability that two individuals might have the same genetic pattern was 2.0 x 10(-4), 1.3 x 10(-4) and 7.2 x 10(-5) for the loci MS43A, g3 and MS1, respectively, and as low as 1.9 x 10(-12) for the three taken together. These data indicate that the genetic diversity of these DNA fingerprinting markers in the Mexican population is high enough to warrant its use in paternity testing and in the identification of individuals in forensic medicine.