High resolution human leukocyte antigen (HLA) class I and class II allele typing in Mexican mestizo women with sporadic breast cancer: case-control study

BACKGROUND

The development of breast cancer is multifactorial. Hormonal, environmental factors and genetic predisposition, among others, could interact in the presentation of breast carcinoma. Human leukocyte antigen (HLA) alleles play an important role in immunity (cellular immunity) and may be important genetic traits. HLAAllele-specific interaction has not been well established. Recently, several studies had been conducted in order to do so, but the results are controversial and in some instances contradictory.

METHODS

We designed a case-control study to quantify the association of HLA class I and II genes and breast cancer. HLA typing was performed by high resolution sequence-specific oligotyping after DNA amplification (PCR-SSOP) of 100 breast cancer Mexican mestizo patients and 99 matched healthy controls.

RESULTS

HLA-A frequencies that we were able to observe that there was no difference between both groups from the statistical viewpoint. HLA-B*1501 was found three times more common in the case group (OR, 3.714; p = 0.031). HLA-Cw is not a marker neither for risk, nor protection for the disease, because we did not find significant statistical differences between the two groups. DRB1*1301, which is expressed in seven cases and in only one control, observing an risk increase of up to seven times and DRB1*1602, which behaves similarly in being present solely in the cases (OR, 16.701; 95% CI, 0.947 - 294.670). DQ*0301-allele expression, which is much more common in the control group and could be protective for the presentation of the disease (OR, 0.078; 95% CI, 0.027-0.223, p = 0.00001).

CONCLUSION

Our results reveal the role of the MHC genes in the pathophysiology of breast cancer, suggesting that in the development of breast cancer exists a disorder of immune regulation. The triggering factor seems to be restricted to certain ethnic groups and certain geographical regions since the relevant MHC alleles are highly diverse. This is the first study in Mexican population where high resolutions HLA typing has been performed in order to try to establish an association with malignancy.

[High and low risk human papilloma virus infection in women with CIN. Differential characteristics]

The objective of this study was to determine high risk human papillomavirus infection (HPV-RH) and factors with cervical intraepithelial neoplasia appears (CIN).

MATERIAL AND METHOD

From October 1998 to January 2000, a case-control study, was made; women with benefit package from Mexican Institute of Social Security. The cases were of the colposcopic clinic of the department of the Hospital Obstetrics and Gynecology Luis Castelazo Ayala, women histologically diagnosed with colposcopy and CIN cervical biopsy, and controls patients with negative cervical uterine cytologic study of the Preventive Medicine Department, Unit of Familiar Medicine No. 8, of Mexico City. Trained personnel obtained information about socioeconomic and reproductive factors did the interview. A cytobrush was used to take the cervical sample for HPV-RH to determine HPV-RH utilizing Hybrid Capture II test. Both bivariate analysis and logistic regression analysis were used for the adjustment of variables.

RESULTS

We analyzed 102 cases and 192 controls, 79% (44/56) of the cases with CIN I and 89% (37/42) of CIN II-III as 21% of controls, respectively, were positive for HPV-RH. Global risk for HPV-RH association to CIN was OR = 40.6 (95% CI, = 17-96.8). Women age was determinative for HPV-RH association to CIN. We observed a high correlation between HPV positive magnitude and CIN degree.

CONCLUSIONS

Frequency of RH-HPV in controls and CIN I is higher than other reports in the literature. HPV was identified as the most important agent associated with this neoplasia, other factors involved and age is an important modifier in HPV-RH and CIN.

Factors involved in control of tissue-specific expression of albumin gene

Elements controlling tissue-specific expression of the rat albumin gene reside within roughly 150 bp upstream of the transcriptional initiation site. We show here by DNAase I footprinting assays that at least four distinct factors present in extracts derived from cells expressing albumin interact with these sequences. One of these factors is closely related or identical to nuclear factor 1 (NF1). Extracts from nonhepatic tissues or from dedifferentiated hepatoma cells that do not transcribe the albumin gene display a different pattern of DNA-protein interactions. Mixing experiments show that the variant pattern of dedifferentiated cells is dominant over that of differentiated ones, suggesting that nonexpressing cells contain dominant negatively acting factors.