PTK6/BRK is expressed in the normal mammary gland and activated at the plasma membrane in breast tumors

Protein Tyrosine kinase 6 (PTK6/BRK) is overexpressed in the majority of human breast tumors and breast tumor cell lines. It is also expressed in normal epithelial linings of the gastrointestinal tract, skin, and prostate. To date, expression of PTK6 has not been extensively examined in the normal human mammary gland. We detected PTK6 mRNA and protein expression in the immortalized normal MCF-10A human mammary gland epithelial cell line, and examined PTK6 expression and activation in a normal human breast tissue microarray, as well as in human breast tumors. Phosphorylation of tyrosine residue 342 in the PTK6 activation loop corresponds with its activation. Similar to findings in the prostate, we detect nuclear and cytoplasmic PTK6 in normal mammary gland epithelial cells, but no phosphorylation of tyrosine residue 342. However, in human breast tumors, striking PTK6 expression and phosphorylation of tyrosine 342 is observed at the plasma membrane. PTK6 is expressed in the normal human mammary gland, but does not appear to be active and may have kinase-independent functions that are distinct from its cancer promoting activities at the membrane. Understanding consequences of PTK6 activation at the plasma membrane may have implications for developing novel targeted therapies against this kinase

Pattern of mycobacterial antigen detection in leprosy Detecção de padrões antigênicos de micobactérias na hanseníase

Immunohistochemistry reaction (Peroxidase anti-peroxidase - PAP) was carried out on fifty-two skin biopsies from leprosy patients with the purpose to identify the antigenic pattern in mycobacteria and to study the sensitivity of this method. Five different patterns were found: bacillar, granular, vesicular, cytoplasmatic and deposits, classified according to the antigenic material characteristics. Deposits (thinely particulate material) appeared more frequently, confirming the immunohistochemistry sensitivity to detect small amounts of antigens even when this material is not detected by histochemical stainings.<br>Foi realizada reação imunohistoquímica (Peroxidase anti-peroxidase-PAP) em 52 biópsias de pele de pacientes com hanseníase com o objetivo de verificar quais os padrões antigênicos das micobactérias e estudar a sensibilidade deste método como auxílio diagnóstico da hanseníase. Foram encontrados cinco padrões diferentes, classificados como bacilar, granular, vesicular, citoplasmático e depósitos, de acordo com a característica do material antigênico. Os depósitos (material finamente particulado) apareceram com maior frequencia confirmando a sensibilidade da imunohistoquímica na detecção de pequenas quantidades de antígeno, cujo material não é mais visto por colorações histoquímicas usuais