We report a case of extranodal NK/T-cell lymphoma, nasal type, with exclusive cerebral localization in a patient with AIDS. The patient presented with neurological alterations, fever and convulsions, so the initial presumptive diagnosis was an opportunistic brain infection. MRI showed a left parietal necrotic lesion and a stereotactic brain biopsy was performed for pathological, microbiological and molecular studies. Histological sections showed an angiocentric and angiodestructive growth pattern and the immunophenotype of this tumor was CD56+, CD45+, CD3+ (cytoplasmic), Granzyme B+ and Perforin+. All the microbiological studies such as bacterial, fungi, micobacteria, Toxoplasma gondii and Cryptococcus determination were negatives. A PCR study with primer specific for EBV viral genome of Bam-Hi-w system was positive. Also, a rearrangement study showed T-cell gene rearrangement with monoclonal appearance. A diagnosis of extranodal NK/T-cell lymphoma was made and the patient died a few days later. This case represents a very rare example of NK/T-cell lymphoma of the brain in a patient with AIDS. The diagnosis of this kind of lymphomas requires a multimodality approach correlating clinical, morphological, immunophenotypic and molecular data.

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Testosterone is essential for the growth and function of the luminal prostate cells, but it is also critical for the development of prostate cancer, which in the majority of the cases derives from luminal cells. Cytochrome P450 3A (CYP3A) enzymes hydroxylate testosterone and dehydroepiandrosterone to less active metabolites, which might be the basis for the association between CYP3A polymorphisms and prostate cancer. However, it is unknown whether the CYP3A enzymes are expressed at relevant levels in the prostate and which polymorphisms could affect this tissue-specific CYP3A activity. Thus, we measured CYP3A4, CYP3A5, CYP3A7, and CYP3A43 mRNA in 14 benign prostatic hyperplasias and ten matched non-tumoral/tumoral prostate samples. We found that CYP3A5 mRNA in non-tumoral prostate tissue was 10% of the average amount of liver samples, whereas the expression of the other CYP3A genes was much lower. Similarly to liver, CYP3A5*3 polymorphism decreased CYP3A5 mRNA content 13-fold. CYP3A5 protein was detected in non-tumoral prostate microsomes by western blot, and immunohistochemistry (IHC) localized CYP3A5 exclusively in the basolateral prostate cells. In contrast to the normal tissue, IHC and RT-PCR showed that tumoral tissue lacked CYP3A5 expression. In conclusion, prostate basolateral cells express high levels of CYP3A5 which dramatically decrease in tumoral tissue. This finding supports an endogenous function of CYP3A5 related to the metabolism of intra-prostatic androgens and cell growth, and that polymorphisms affecting CYP3A5 activity may result in altered prostate cancer risk and aggressiveness.

The purpose of this review is to evaluate case reports of papillary squamous cell carcinoma (PSCC) of the upper aerodigestive tract (UADT) to assess its relationship with human papillomavirus (HPV). The medical literature was searched for case reports of this condition. A total of 115 cases of PSCC were found that described the condition in sufficient detail. HPV detection was performed in only 22 of the 115 cases of PSCC (19%), and 11 of the 22 cases (50%) are related to this virus. The majority of cases related to HPV are produced by low-risk HPV type 6 followed by high-risk HPV type 16. Today, the association of HPV with PSCCs seems unclear because in the majority of patients tests were not performed for the detection of the HPV. This association should be clearly established to make a correct diagnosis and propose the best therapeutic strategies, such as new vaccines.

Objective: The Her2/neu status is of great clinical value in breast tumor patients. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) techniques are the test of choice for many practicing pathologies. The main objective of this retrospective study was to investigate the relationship between Her2/neu breast cancer amplification and overexpression (DNA, mRNA and protein). Methods: To accomplish this goal, we evaluated Her2/neu mRNA expression by real-time quantitative RT-PCR, gene amplification by FISH and protein expression by IHC. Results: An excellent correlation between FISH and IHC Her2/neu results was observed, confirming that protein levels were directly related to DNA amplification. Polysomy 17 was frequently found in tumors showing Her2/neu overexpression. However, we did not find any statistically significant correlation among DNA, mRNA and protein levels, suggesting that Her2/neu could be post-transcriptionally regulated. Conclusions: There was a highagreement between Her2/neu gene amplification and protein overexpression but not mRNA expression levels. Nevertheless, IHC3+ and FISH-positive tumors indicated higher expression levels of Her2/neu mRNA by RT-PCR than those observed in IHC and FISH-negative tumors. These findings question the relevance of quantitative RT-PCR in routine assessment of Her2/neu overexpression in human breast cancer in the clinical laboratory setting.