A multi-institutional study of feasibility, implementation, and early clinical results with noninvasive breast brachytherapy for tumor bed boost.

Purpose: To evaluate the feasibility, implementation, and early results of noninvasive breast brachytherapy (NIBB) for tumor bed boost with whole breast radiation therapy (WBRT).

Methods And Materials: NIBB is a commercially available (AccuBoost, Billerica, MA) mammography-based, brachytherapy system in which the treatment applicators are centered on the planning target volume (PTV) to direct (192)Ir emissions along orthogonal axes. A privacy-encrypted online data registry collected information from 8 independent academic and community-based institutions.

Effect of DNA polymerase beta loop variants on discrimination of O6-methyldeoxyguanosine modification present in the nucleotide versus template substrate.

We have examined the mechanism of DNA polymerase beta (pol beta) lesion discrimination using alkylated dNTP versus alkylated DNA template substrates and the pol beta variants R253M and E249K. Both of these amino acid variants are located in the loop region of the palm domain and are known to play a role in pol beta fidelity and discrimination of 3'-azido-3'-deoxythymidine triphosphate substrates. We observed that these variants affect O(6)-methyldeoxyguanosine- (m6G-) modified dNTP discrimination without affecting m6G template translesion synthesis.