Rosenda Peñaloza

A molecular analysis by gene expression profiling reveals Bik/NBK overexpression in sporadic breast tumor samples of Mexican females

BackgroundBreast cancer is one of the most frequent causes of death in Mexican women over 35 years of age. At molecular level, changes in many genetic networks have been reported as associated with this neoplasia. To analyze these changes, we determined gene expression profiles of tumors from Mexican women with breast cancer at different stages and compared these with those of normal breast tissue samples.Methods32P-radiolabeled cDNA was synthesized by reverse transcription of mRNA from fresh sporadic breast tumor biopsies, as well as normal breast tissue. cDNA probes were hybridized to microarrays and expression levels registered using a phosphorimager. Expression levels of some genes were validated by real time RT-PCR and immunohistochemical assays.ResultsWe identified two subgroups of tumors according to their expression profiles, probably related with cancer progression. Ten genes, unexpressed in normal tissue, were turned on in some tumors. We found consistent high expression of Bik gene in 14/15 tumors with predominant cytoplasmic distribution.ConclusionRecently, the product of the Bik gene has been associated with tumoral reversion in different neoplasic cell lines, and was proposed as therapy to induce apoptosis in cancers, including breast tumors. Even though a relationship among genes, for example those from a particular pathway, can be observed through microarrays, this relationship might not be sufficient to assign a definitive role to Bik in development and progression of the neoplasia. The findings herein reported deserve further investigation.

Serum IgG and IgD and levels in some infectious and noninfectious diseases

Serum IgG and IgD levels were determined in the following groups: professional blood donors, healthy smokers and patients with acute hepatitis, with acute salmonellosis, with hepatic cirrhosis, with cancer (prostate, lung and gastrointestinal tract) and with benign diseases of the same organs as the cancer patients. IgG was significantly increased in the groups of patients with hepatitis, hepatic cirrhosis and cancer. IgD values showed a wide dispersion in all the groups, which do not allow for comparisons among means. For that reason, linear regression analysis between IgG and IgD was done, the results being significant only in the two groups with infectious diseases (acute hepatitis and acute salmonellosis), which suggest that IgD could be involved in the immune response against their respective pathogenic agents.

Frequency of haplotypes in the beta globin gene cluster in a selected sample of the mexican population

Five polymorphic restriction enzyme sites in the beta globin gene cluster (HindIII Gγ‐Hind III Aγ‐, Ava IIINV−2β‐and Hpa I and Bam HI 3′β‐globin gene) were studied in individuals from 13 families: 13 homozygote patients for sickle cell anemia, two double heterozygotes (one SC and one S/βThal), 35 AS heterozygotes (23 parents and 12 siblings), one father (A/βThal), and three normal siblings. In addition, 17 normal unrelated Mexican subjects were studied. All subjects were from the state of Veracruz on the coast of the Gulf of Mexico. The Southern blot technique was used. Fifteen haplotypes were identified in the 142 chromosomes. Five were the most frequent: two haplotypes, (+−+++) (52.4%) and (−−+−+) (19.0%) were associated with βS chromosomes; two haplotypes, (−−+++) (38.2%) and (−−−++) (19.7%), were linked with βA chromosomes, and the fifth (−−++−) was present in both types of chromosomes. Haplotype (+−+++) corresponded to the Bantu or Senegal type. With Hinc II analysis after PCR amplification in both the 5′ and 3′ regions of the ψβ‐globin gene, it was possible to distinguish between these African types, as in the former both restriction sites are absent. This analysis was done in 23 βS and 10 βA subjects. All βS chromosomes disclosed the Bantu type, while βA were similar to Caucasians. Bantu and Benin haplotypes have been found with high frequency in African populations, indicating the great influence of African genes in the population of the Mexican coasts. In addition, two previously unidentified haplotypes were found: (++−−+) and (−++++). These can be explainded by crossing‐over events and/or by new mutations.

Blood groups and red cell acid phosphatase types in a Mixteca population resident in Mexico City.

Several blood groups, ABO, Rh, Ss, Fy, Jk, and red cell acid phosphatase (ACP) types were studied in a native Mixteca population that has resided in Mexico City since 1950. Gene frequencies were obtained and used to establish admixture estimates with blacks and whites. The subjects came from three different geographical areas: High Mixteca, Low Mixteca, and Coast Mixteca. All frequencies were in Hardy‐Weinberg equilibrium. The difference in the ABO frequencies was statistically significant when subjects from the three areas were compared simultaneously. Rh frequencies differed only between the High and the Low Mixteca populations. The ACP frequencies were similar between the Low Mixteca population and a previously reported Mestizo population. However, there were significant differences between the High Mixteca group and a Mestizo population, all the subjects being from Oaxaca. This is the first report of Ss, Fy, Jk, and ACP frequencies in a Mixteca population. Am. J. Hum. Biol. 11:525–529, 1999.