Correlation between salivary and serum CA15-3 concentrations in patients with breast cancer.

The early detection of breast cancer enables the use of less aggressive treatment and increases patient survival. The transmembrane glycoprotein mucin 1, which is also known as cancer antigen 15-3 (CA15-3), is aberrantly glycosylated and overexpressed in a variety of epithelial cancers, and serves a crucial role in the progression of the disease. CA15-3 is currently used as a marker of breast cancer. In the present study, CA15-3 concentrations in saliva and blood of patients with breast cancer were evaluated to test new assays to detect salivary CA15-3 in addition to ELISA and its diagnostic value. To the best of our knowledge, there are no previous reports of the use of chemiluminescence assay (CLIA) and electrochemiluminescence assay (ECLIA) in saliva. Saliva and blood were collected on the same day from patients with breast cancer (n=26) and healthy controls (n=28). For each subject, the level of serum CA15-3 was measured using ECLIA, and the level of salivary CA15-3 was measured using ECLIA, CLIA and enzyme-linked immunosorbent assay (ELISA). ELISA and CLIA were able to detect CA15-3 in saliva; however, ECLIA could not detect salivary CA15-3. There was no significant difference between the mean serum and salivary CA15-3 levels in patients with breast cancer or healthy controls. The levels of CA15-3 were highest for luminal breast cancer subtypes and stage IV cases. A moderate correlation was observed between salivary and serum CA15-3 levels as measured by ELISA in breast cancer patients (r=0.56; P=0.0047). The results demonstrated that ECLIA was not a good method to detect salivary CA15-3, although it is the gold standard for detecting serum CA15-3. The presence of CA15-3 in saliva was confirmed, and this will be useful in future research. Further investigations are necessary to confirm the ability to detect salivary CA15-3 and its correlation with serum CA15-3.

LEUKOTOXIC ACTIVITY OF ACTINOBACILLUS ACTINOMYCETEMCOMITANS ISOLATED FROM HUMAN AND NON-HUMAN PRIMATES

Actinobacillus actinomycetemcomitans is a clinically relevant periodontopathogenic Gram-negative coccobacillus that produces a leukotoxin of the RTX cytolysin family. In this study, we evaluated the leukotoxic activity of A. actinomycetemcomitans strains isolated from human and marmosets by Trypan blue exclusion and by the chemiluminescence assays. Among eight A. actinomycetemcomitans human strains studied, two (P2.17 and P8.12) were classified as high leukotoxin producers and among eight marmoset strains, one (M22.11) showed high leukotoxin production, as determined by Trypan blue exclusion assay. The reference strains ATCC 29523 and FDC Y4 respectively behaved like moderate and low producers. The chemiluminescence assay was used to evaluate the leukotoxic activity of M22.11 and P2.17 strains submitted to different growth conditions. Leukotoxic activity was detected on cells at the logarithmic phase and was similar under anaerobic and microaerophilic growth conditions. It was greatly reduced when cells were grown at glucose concentrations lower or higher than 0.75% (0.25% and 1.5%) in thioglycolate medium. Leukotoxin production mainly by the M22.11 strain was low in BHI broth, whereas production in TSB medium showed a similar level as in thioglycolate broth medium. Sodium bicarbonate at 10 mM did not affect leukotoxin production.

Actinobacillus actinomycetemcomitans é um cocobacilo Gram negativo, periodontopatógeno clinicamente importante, que produz uma leucotoxina pertencente à família das citolisinas RTX. Neste estudo, avaliou-se a atividade leucotóxica de amostras de A. actinomycetemcomitans isoladas de seres humanos e de calitriquídeos pelos métodos de exclusão de azul de Tripan e quimioluminescência. Duas (P2.17 e P8.12) entre oito amostras de A. actinomycetemcomitans isoladas de seres humanos, e uma (M22.11) entre 8 amostras isoladas de sagüis se apresentaram como altamente produtoras de leucotoxina, como determinado pelo teste de exclusão de azul de Tripan. As amostras de referências de A. actinomycetemcomitans ATCC 29523 e FDC Y4 se comportaram como média e baixa produtoras de leucotoxina, respectivamente. O teste de quimioluminescência foi usado para avaliar a atividade leucotóxica das amostras M22.11 e P2.17 submetidas a diferentes condições de crescimento. A atividade leucotóxica foi detectada em células durante a fase logarítmica e foi similar sob crescimento em anaerobiose e microaerofilia. A atividade leucotóxica foi muito reduzida quando as células foram crescidas em concentrações de glicose mais baixa e mais alta que 0,75% (0,25% e 1,5%), em meio tioglicolato. A produção de leucotoxina, especialmente pela amostra M22.11, foi mais baixa em caldo BHI, enquanto em meio TSB a produção foi em nível similar a aquele em meio tioglicolato. Bicarbonato de sódio 10mM não afetou a produção de leucotoxina.