Renata Tucci

Homeobox genes: a molecular link between development and cancer

Homeobox genes are regulatory genes encoding nuclear proteins that act as transcription factors, regulating aspects of morphogenesis and cell differentiation during normal embryonic development of several animals. Vertebrate homeobox genes can be divided in two subfamilies: clustered, or HOX genes, and nonclustered, or divergent, homeobox genes. During the last decades, several homeobox genes, clustered and nonclustered ones, were identified in normal tissue, in malignant cells, and in different diseases and metabolic alterations. Homeobox genes are involved in the normal teeth development and in familial teeth agenesis. Normal development and cancer have a great deal in common, as both processes involve shifts between cell proliferation and differentiation. The literature is accumulating evidences that homeobox genes play an important role in oncogenesis. Many cancers exhibit expression of or alteration in homeobox genes. Those include leukemias, colon, skin, prostate, breast and ovarian cancers, among others. This review is aimed at introducing readers to some of the homeobox family functions in normal tissues and especially in cancer.

Comparative immunoprofile of polymorphous low-grade adenocarcinoma and canalicular adenoma

Immunohistochemistry is an important tool when dealing with salivary gland neoplasms. Canalicular adenoma and polymorphous low-grade adenocarcinoma may share some histologic characteristics that can cause difficulties in their separation. In the present study, cases of polymorphous low-grade adenocarcinoma and canalicular adenoma were submitted to a panel of antibodies to evaluate the differences in their immunoprofiles. The results obtained showed that, while vimentin is only expressed by polymorphous low-grade adenocarcinoma, CK7 and CK8 are present in both neoplasms. Therefore, vimentin is the best marker to differentiate between these tumors.

HOXB5 expression in oral squamous cell carcinoma

UNLABELLED Human HOX genes encode transcription factors that act as master regulators of embryonic development. They are important in several processes such as cellular morphogenesis and differentiation. The HOXB5 gene in particular has been reported in some types of neoplasm, but not in oral cancer. OBJECTIVE The present study investigated the expression of HOXB5 in oral squamous cell carcinoma (SCC) and in non-tumoral adjacent tissues, focusing on verifying its possible role as a broad tumor-associated gene and its association with histopathological and clinical (TNM) characteristics. MATERIAL AND METHODS RT-PCR was performed to amplify HOXB5 mRNA in 15 OSCCs and adjacent non-tumoral epithelium. A possible association with TNM and histopathologic data was verified by the chi-square and post-hoc t-test. RESULTS HOXB5 was amplified in 60% non-tumoral epithelium and in 93.3% carcinomas. No statistically significant differences were found regarding the HOXB5 mRNA expression and TNM or histological grade. CONCLUSION HOXB5 is expressed in OSCCs and its role in cancer progression should be further investigated.