Alejandra Mantilla

Stomach microbiota composition varies between patients with non-atrophic gastritis and patients with intestinal type of gastric cancer

We aimed to characterize microbiota of the gastric mucosa as it progress to intestinal type of cancer. Study included five patients each of non-atrophic gastritis (NAG), intestinal metaplasia (IM) and intestinal-type gastric cancer (GC). Gastric tissue was obtained and DNA extracted for microbiota analyses using the microarray G3 PhyloChip. Bacterial diversity ranged from 8 to 57, and steadily decreased from NAG to IM to GC (p = 0.004). A significant microbiota difference was observed between NAG and GC based on Unifrac-presence/absence and weighted-Unifrac-abundance metrics of 283 taxa (p < 0.05). HC-AN analyses based on presence/absence of 238 taxa revealed that GC and NAG grouped apart, whereas IM overlapped with both. An ordinated analyses based on weighted-Unifrac distance given abundance of 44 taxa showing significance across categories revealed significant microbiota separation between NAG and GC. This study is the first to show a gradual shift in gastric microbiota profile from NAG to IM to GC.

No association between Epstein-Barr Virus and Mouse Mammary Tumor Virus with breast cancer in Mexican women.

Breast cancer is the most frequent malignancy affecting women worldwide. It has been suggested that infection by Epstein Barr Virus (EBV), Mouse Mammary Tumor Virus or a similar virus, MMTV-like virus (MMTV-LV), play a role in the etiology of the disease. However, studies looking at the presence of these viruses in breast cancer have produced conflicting results, and this possible association remains controversial. Here, we used polymerase chain reaction assay to screen specific sequences of EBV and MMTV-LV in 86 tumor and 65 adjacent tissues from Mexican women with breast cancer. Neither tumor samples nor adjacent tissue were positive for either virus in a first round PCR and only 4 tumor samples were EBV positive by a more sensitive nested PCR. Considering the studys statistical power, these results do not support the involvement of EBV and MMTV-LV in the etiology of breast cancer.

Evidence of Epstein-Barr Virus Association with Gastric Cancer and Non-Atrophic Gastritis

Different lines of evidence support an association between Epstein-Barr virus (EBV) and gastric cancer (GC). The main understood risk factor to develop GC is infection by Helicobacter pylori (H. pylori), which triggers a local inflammatory response critical for progression from gastritis to GC. The role of EBV in early inflammatory gastric lesions has been poorly studied. A recent study proposed a cutoff value of 2000 EBV particles to identify patients with increased chances of infection of the gastric epithelium, which may favor the inflammatory process. To better understand the role of EBV in cancer progression, we analyzed 75 samples of GC, 147 control samples of non-tumor gastric tissue derived from GC patients and 75 biopsies from patients with non-atrophic gastritis (NAG). A first-round PCR was used for EBV detection in tumor and non-tumor controls and a more sensitive nested PCR for gastritis samples; both PCRs had lower detection limits above the proposed cutoff value. With this strategy 10.67% of GC, 1.3% of non-tumor controls and 8% of gastritis samples were found positive. An EBER1 in situ hybridization showed EBV infection of epithelial cells in GC and in a third of NAG samples, while in the other NAGs infection was restricted to the mononuclear cell infiltrate. EBV-positive GCs were enriched in lace and cribriform patterns, while these rare patterns were not observed in EBV negative samples. Our results support a role for EBV in GC and early precursor lesions, either as directly oncogenic infecting epithelial cells or indirectly as an inflammatory trigger.

RET Oncogene Mutations in Medullary Thyroid Carcinoma in Mexican Families

BACKGROUND Different RET oncogene mutations have been found to be associated with inherited medullary thyroid carcinoma (MTC) in the context of three different syndromes including multiple endocrine neoplasia types 2A (MEN 2A) and 2B (MEN 2B) and familial medullary thyroid carcinoma (FMTC). These mutations have been recorded in different populations, but to date there is no corresponding study in Mexican families. Our purpose was identification of RET mutations in Mexican families with inherited or sporadic MTC (SMTC) and search for RET protein expression as prognostic marker in MTC tumors. METHODS Nine unrelated families with MTC corresponding either to two MEN 2A, three MEN 2B, or four SMTC were studied. Screening of exons 10, 11, and 13-16 of RET oncogene in DNA from circulating lymphocytes and tumor samples were analyzed. Immuno- staining for RET was performed in the corresponding tumor. RESULTS Germline 918 ATG-->ACG RET mutation was present in three unrelated MEN 2B individuals and corresponding somatic mutation in one individual with SMTC; 634 TGC-->TTC RET mutation was detected in two related patients in an MEN 2A family and the 634 TGC-->TAC RET mutation was detected in 12 related individuals from a second MEN 2A family. RET protein expression was detected in all MTC tumors showing different staining intensity. CONCLUSIONS RET mutations found in Mexican patients with MTC are similar to those previously reported in several MTC families worldwide. This indicates that RET mutations are highly conserved and that MTC etiology does not depend to a great extent on environmental factors or ethnic differences. Detection of RET protein in MTC tissue sections is not useful as prognostic marker.

Germline Mutations in PALB2, BRCA1, and RAD51C, Which Regulate DNA Recombination Repair, in Patients With Gastric Cancer

Up to 10% of cases of gastric cancer are familial, but so far, only mutations in CDH1 have been associated with gastric cancer risk. To identify genetic variants that affect risk for gastric cancer, we collected blood samples from 28 patients with hereditary diffuse gastric cancer (HDGC) not associated with mutations in CDH1 and performed whole-exome sequence analysis. We then analyzed sequences of candidate genes in 333 independent HDGC and non-HDGC cases. We identified 11 cases with mutations in PALB2, BRCA1, or RAD51C genes, which regulate homologous DNA recombination. We found these mutations in 2 of 31 patients with HDGC (6.5%) and 9 of 331 patients with sporadic gastric cancer (2.8%). Most of these mutations had been previously associated with other types of tumors and partially co-segregated with gastric cancer in our study. Tumors that developed in patients with these mutations had a mutation signature associated with somatic homologous recombination deficiency. Our findings indicate that defects in homologous recombination increase risk for gastric cancer.

Hox B4 as potential marker of non-differentiated cells in human cervical cancer cells

BackgroundCervical cancer (CC) is a common malignancy in women worldwide. Cervical tumorigenesis involves a multistep process in which accumulations of genetic alterations are present. Homeotic genes, such as HOX gene re-expression, have been reported in a wide variety of tumors.MethodsIn order to know the role of HOX B4 gene expression in CC, in the present study, two-dimensional polyacrylamide gel electrophoresis, matrix-assisted laser desorption/ionization, and time-of-flight mass spectrometry were used for differential screening of protein expression in CC. Immunohistochemical analysis was performed on the cervical tissue microarray (TMA) to detect the Hox B4 protein.ResultsHox B4 peptide was detected among 15 increased spots differentially observed in CC. Using TMA, Hox B4 protein was also immunodetected in the nuclei of cervical epithelial tumor cells, while in normal cervical epithelium, it was absent. Interestingly, it was possible to detect the Hox B4 protein in the precursor lesions.ConclusionsHox B4 protein is present in the precursor lesions as CC cells, suggesting that Hox B4 could be a protein related to the neoplastic state (non-differentiated cells) of human cervical epithelium.

High prevalence of RET tyrosine kinase activation in Mexican patients with papillary thyroid carcinomas.

RET/PTC oncogene expression is restricted to papillary thyroid carcinomas (PTC). At least three forms of this oncogene have been described. These are generated by the rearrangement of the 5′-terminal region of different expressed genes with the tyrosine-kinase (TK) domain of the ret proto-oncogene. Several studies showing the correlation between the expression of this oncogene, clinical outcome, and histological subtypes have been published. Thirty-five paraffin-embedded PTC samples from patients without a history of radiation exposure were studied. Immunohistochemistry (IHC) and in situ hybridization (ISH) were used to determine a possible correlation between RET activation, clinical outcome, and tumor subtype. Almost half of the studied cases presented with tumoral extension or metastases. Ret gene transcripts and protein were found in all PTC variants as well as in their corresponding metastases. In contrast, none of the follicular adenomas, goiters, or normal follicular cells from the thyroid gland showed evidence of ret activation. We observed a high frequency of ret expression in PTCs, suggesting that ret activation is a common event in nonradiation-related PTC from Mexican patients.

Penetrance of inherited medullary thyroid carcinoma and genotype-phenotype correlation in a large multiple endocrine neoplasia type 2A family with C634Y RET mutation.

Multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid carcinoma (FMTC) are characterized by development of medullary thyroid carcinoma (MTC) and caused by germline RET mutations. Patients with MEN 2A also develop pheochromocytoma and/or hyperparathyroidism (HPT). However, MEN 2A-affected individuals could display the FMTC phenotype at first clinical manifestation. To establish the correct phenotype and improve clinical management of patients affected by hereditary MTC, clinical screening, RET mutational analysis, penetrance of MTC, and genotype-phenotype correlation were performed in a large, suspected FMTC kindred of 86 individuals. Germline C634Y RET mutation was confirmed in 22 individuals, 15 of whom were thyroidectomized when high serum calcitonin levels were detected. MTC was confirmed in 12 individuals and C-cell hyperplasia in 3. HPT was detected in two patients. High penetrance of MTC at young age (79% at 30 yr of age) was found. This family was considered to be affected by FMTC for several years because MTC was the sole clinical manifestation. However, our results allowed reclassifying the family as MEN 2A, thereby improving clinical management of family members. Our findings regarding penetrance and genotype-phenotype correlation suggest that patients considered to have FMTC may in fact have MEN 2A in some kindreds.

IL-1β, IL-8, and Matrix Metalloproteinases-1, -2, and -10 Are Enriched upon Monocyte–Breast Cancer Cell Cocultivation in a Matrigel-Based Three-Dimensional System

Breast cancer remains the first cancer-related cause of death in women worldwide, particularly in developing countries in which most cases are diagnosed in late stages. Although most cancer studies are based in the genetic or epigenetic changes of the tumor cells, immune cells within the tumor stroma often cooperate with cancer progression. Particularly, monocytes are attracted to the tumor primary site in which they are differentiated into tumor-associated macrophages that facilitate tumor cell invasion and metastasis. In this study, we used three-dimensional cultures to form acini-like structures to analyze the inflammatory secretion profile of tumor cells individually or in co-culture with monocytes. Breast cancer cell lines and primary isolates from eight Mexican patients with breast cancer were used. We found high levels of RANTES/CCL5, MCP-1/CCL2, and G-CSF in the breast cancer individual cultures, supporting an important recruitment capacity of monocytes, but also of neutrophils. The co-cultures of the tumor cells and monocytes were significantly enriched with the potent pro-inflammatory cytokines interleukin (IL)-1β and IL-8, known to support malignant progression. We also found that the interaction of tumor cells with monocytes promoted high levels of matrix metalloproteinases (MMP)-1, MMP-2, and MMP-10. Our study supports that a key event for malignant progression is the recruitment of different immune cell populations, which help to sustain and enhance a chronic inflammatory microenvironment that highly favors tumor malignancy.