Surveillance of Disease Progression in Metastatic Breast Cancer by Molecular Counting of Circulating Tumor DNA Using Plasma-SeqSensei Breast Cancer in Vitro Diagnostics Assay.

Circulating tumor DNA (ctDNA) quantification surpasses cancer antigen 15 to 3 for metastatic breast cancer surveillance. Clinical translation, however, is limited because of uncertainties about the optimal method and clinically valid ctDNA decision thresholds. Plasma-SeqSensei Breast Cancer IVD kit (PSS) is a novel assay for ctDNA molecular counting, detecting ≥0.

Rational thresholding of circulating tumor DNA concentration for improved surveillance of metastatic breast cancer.

Background: The use of circulating tumor DNA (ctDNA) concentration for metastatic cancer surveillance is promising, but uncertainty remains about cut-offs with clinical validity.

Materials And Methods: This observational study recruited 136 subjects with advanced metastatic breast cancer (irrespective of ERBB2/hormone receptor status) for sequencing of their primary tumor in search for PIK3CA hotspot variants amenable for monitoring by droplet digital PCR (ddPCR). The study analyzed 341 on-treatment samples from 19 patients with PIK3CA variants H1047R or E545K enrolled for long-term (median 85 weeks, range 13-125 weeks), frequent (every 3-5 weeks, median of 14 time points per subject, range 2-29) blood sampling for ctDNA quantification by ddPCR, orthogonally validated by deep sequencing.

Adaptation under dichromatic illumination.

Over the years, many CATs (chromatic adaptation transforms) have been developed, such as CMCCAT97, CAT02 and CAT16, to predict the corresponding colors under different illuminants. These CATs were derived from uniform simple stimuli surrounded by a uniform background with a single illuminant. Although some mixed adaptation models have been proposed in literature to predict the adaptation under more than one illuminant, these models are typically limited to a certain scene and exclude the impact of spatial complexity.