HOXB homeobox gene expression in cervical carcinoma.

The homeobox (HOX) genes are a family of transcription factors that bind to specific DNA sequences in target genes regulating gene expression. Thirty-nine HOX genes have been mapped in four conserved clusters: A, B, C, and D; they act as master genes regulating the identity of body segments along the anteroposterior axis of the embryo. The role played by HOX genes in adult cell differentiation is unclear to date, but growing evidence suggests that they may play an important role in the development of cancer. To study the role played by HOX genes in cervical cancer, in the present work, we analyzed the expression of HOXB genes and the localization of their transcripts in human cervical tissues. Reverse transcription-polymerase chain reaction analysis and nonradioactive RNA in situ hybridization were used to detect HOXB expression in 11 normal cervical tissues and 17 cervical carcinomas. It was determined that HOXB1, B3, B5, B6, B7, B8, and B9 genes are expressed in normal adult cervical epithelium and squamous cervical carcinomas. Interestingly, HOXB2, HOXB4, and HOXB13 gene expression was found only in tumor tissues. Our findings suggest that the new expression of HOXB2, HOXB4, and B13 genes is involved in cervical cancer.

A simple method for the construction of small format tissue arrays.

Tissue arrays can evaluate molecular targets in high numbers of samples in parallel. Array construction presents technical difficulties and tissue arrayers are expensive, particularly for small and medium sized laboratories. This report describes a method for the construction of 36 sample arrays using widely available materials. A blunted 16 gauge needle for bone marrow aspiration was used to extract paraffin wax cylinders and manually define a 6 x 6 matrix on a blank paraffin wax block. Tissue cores from 36 paraffin wax embedded premalignant lesions and invasive cervical carcinomas were injected into the matrix using a 14 gauge needle. This tissue array was sectioned using a standard microtome and used for the immunodetection of CD44 variant 9 and interleukin 18 with satisfactory results. This method can be applied in any laboratory, without the need of specialised equipment, offering a good alternative for the wider application of tissue arrays.

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.

[Frequency of gastric lymphoma at 6 hospitals in Mexico City]. / Frecuencia de linfoma gástrico en seis hospitales de la Ciudad de México.

BACKGROUND: Gastric lymphoma has been traditionally considered a rare neoplasm that constitutes 1-5% of malignant gastric tumors. Two studies performed in Mexico in 1960 and 1966 found that only 1.9% and 1% of gastric neoplasms were lymphomas. Nevertheless, some studies made in the U.S. and in some European countries in recept decades have revealed an increase in the frequency of this neoplasm. A recent study made at two National Health Institutes in Mexico City (Instituto Nacional de Cancerología and Instituto Nacional de la Nutrición) revealed a remarkable increase in the frequency of gastric lymphoma (9.3% and 10.3%, respectively) in recent years. AIM: To define whether there is an actual increase of lymphoma in our population and whether it includes other hospitals in Mexico City that provides attention to populations different from those who attend referral centers. MATERIALS AND METHODS: Six hospitals in Mexico City were selected, including two National Health Institutes (Instituto Nacional de la Nutrición and Instituto Nacional de Cancerología), two private general hospitals used by patient with a high socioeconomic level (Hospital Español and Hospital Inglés), and two public general hospitals frequented by low-income patients (hospital Juárez and Hospital General de México). In each case, the gastric lymphomas diagnosed in each participant hospitals in the last 5 years were registered. For comparative purpose, diagnosed cases of gastric adenocarcinoma during the same period were also registered. Other types of gastric neoplasms were excluded from the study because they formed a very heterogeneous group and represented a minimal proportion of malignant gastric tumors. Age and sex of each patient were included for all lymphomas. RESULTS: A total of 879 malignant gastric neoplasms were included in our study. The relative percentage for gastric lymphoma by institution in descendent order was Hospital Español 25.4%; Instituto Nacional de la Nutrición 13.7%, Hospital Inglés 11.5%, Hospital General de México 8.5%, Instituto Nacional de Cancerología 6%, and Hospital Juárez 6%. Mean general frequency taking into account the six hospitals was 9.1%. CONCLUSIONS: Frequency of gastric lymphomas in all analyzed institutions was higher than that reported in most series in the medical literature (1-5%) and that reported for the Mexican population in 1960 and 1966. The increase was most remarkable in hospitals attended by patients with high incomes (Hospital Español, Hospital Inglés), although the total number of neoplasms reported by these institutions was smaller than that reported by hospitals were by patients with lower incomes (Hospital Juárez, Instituto Nacional de Cancerología). The reason for this increase is unknown, but one might speculate that some strains of Helicobacter pylori, nutritional factors, and ethnic differences could be involved. Both gastroenterologists and pathologists must recognize the increase of this neoplasm because unlike gastric adenocarcinoma, gastric lymphoma is a curable disease in a high percentage of cases.