Benign and borderline phyllodes tumors of the breast: Clinicopathologic analysis of 205 cases with emphasis on the surgical margin status and local recurrence rate.

BACKGROUND: The management of benign and borderline phyllodes tumors of the breast with a positive surgical margin is still controversial. Our aim in this study was to evaluate the impact of surgical margin status on the local recurrence rate of benign and borderline phyllodes tumors. METHODS: We reviewed 205 phyllodes tumors (191 benign, 14 borderline) that were surgically excised at our hospital between 2005 and 2019. Follow-up information extending to at least 6 months after surgery was retrieved from the clinical, radiology, and pathology records. RESULTS: The initial surgical margin was negative in 54 (26%) cases, close (≤ 1 mm) in 29 (14%) cases, and positive in 122 (60%) cases. Approximately half of the cases with a close margin and two-third of the cases with a positive margin underwent re-excision to obtain negative margins. Three (2.3%) local recurrences were observed among 131 cases with follow-up information, all three with benign phyllodes tumor. Of these three patients, one had a positive final margin, and two had negative final margins. There was no significant difference in the rate of local recurrence between PT with a positive surgical margin versus a close and negative margin. CONCLUSION: The study results suggest that close clinical and radiologic follow-up may provide a better course of management rather than re-excision when managing positive margins in benign and borderline phyllodes tumors.

Interaction of a Cationic Porphyrin and Its Metal Derivatives with G-Quadruplex DNA.

G-quadruplex (GQ) structures formed from guanine-rich sequences are found throughout the genome and are overrepresented in the promoter regions of some oncogenes, at the telomeric ends of eukaryotic chromosomes, and at the 5'-untranslated regions of mRNA. Interaction of small molecule ligands with GQ DNA is an area of great research interest to develop novel anticancer therapeutics and GQ sensors. In this paper we examine the interactions of TMPyP4, its isomer TMPyP2 (containing N-methyl-2-pyridyl substituents, N-Me-2Py) as well as two metal derivatives ZnTMPyP4 and CuTMPyP4 with GQs formed by dT4G4 and dT4G4T in 100 mM K+ or Na+ conditions. The DNA sequences were chosen to elucidate the effect of the 3'-T on the stabilization effect of porphyrins, binding modes, affinities, and stoichiometries determined via circular dichroism melting studies, UV-vis titrations, continuous variation analysis, and fluorescence studies. Our findings demonstrate that the stabilizing abilities of porphyrins are stronger toward (dT4G4)4 as compared to (dT4G4T)4 (ΔTm is 4.4 vs -6.4 for TMPyP4; 12.7 vs 5.7 for TMPyP2; 16.4 vs 12.1 for ZnTMPyP4; and 1.9 vs -8.4 °C for CuTMPyP4) suggesting that the 3'G-tetrad presents at least one of the binding sites. The binding affinity was determined to be moderate (Ka ∼ 106-107 µM-1) with a typical binding stoichiometry of 1:1 or 2:1 porphyrin-to-GQ. In all studies, ZnTMPyP4 emerged as a ligand superior to TMPyP4. Overall, our work contributes to clearer understanding of interactions between porphyrins and GQ DNA.