In phyllodes tumour of the breast expression of c-kit but not of ALDH1A1 is associated with adverse clinico-pathological features

Better survival was found in patients treated with breast-conserving surgery compared with mastectomy in malignant phyllodes tumor of the breast

Malignant phyllodes tumor of the breast (MPTB) is a rare type of breast cancer. The prognosis between breast-conserving surgery (BCS) and mastectomy remains unclear in MPTB. Therefore, long-term survival was investigated between BCS and mastectomy in MPTB via the Surveillance, Epidemiology, and End Results (SEER) database. MPTB patients with T1-2/N0 stage between 2000 and 2015 from SEER database were retrospectively reviewed. Prognosis between different surgical approaches was assessed by Kaplan-Meier curves and Cox proportional hazards analysis. A total of 795 patients were enrolled with a median follow-up of 126 months. BCS was associated with significantly increased 10-year overall survival (OS) (89.2% vs. 81.1%, p = 0.002) and breast cancer-specific survival (BCSS) (95.2% vs. 90%, p = 0.004) compared with mastectomy. Multivariate analysis showed better OS (HR = 0.587, 95% CI 0.406-0.850, p = 0.005) and BCSS (HR = 0.463, 95%CI 0.267-0.804, p = 0.006) in the BCS group than the mastectomy group. After 1:1 propensity score matching (PSM), improved 10-year OS (89.2% vs.81%, p = 0.023) and BCSS (95.8% vs. 90.1%, p = 0.033) were observed in BCS compared with mastectomy. This study found the survival benefit of BCS over mastectomy in patients with early-stage MPTB. BCS should be recommended as a priority in MPTB patients when both surgical approaches are feasible.

Periductal Stromal Tumor of the Breast: One Institution's Review of 6 Tumors Over a 22 Year Period With Immunohistochemical Analysis

Introduction. Periductal stromal tumor (PST) of the breast is a rare fibroepithelial neoplasm with controversial pathogenesis. Methods. A retrospective search of our Pathology database from 2000 to 2021 identified 6 PST, all evaluated according to the Armed Forces Institute of Pathology (AFIP) criteria. Immunohistochemistry for CD10, CD34, KIT, GATA3, p63, SOX10, ER, PR, HER2, smooth muscle actin (SMA), beta-catenin, and myogenin was performed as well. Results. All 6 patients were female and age ranged from 29 to 55 years (mean 40 years). Tumor size ranged from 2.9 to 5.9 cm (mean 3.0 cm). Data showed absence of leaf-like architecture (0/6), at least moderate hypercellularity (6/6), lack of a circumscribed border (5/6), coalescing nodules with intermixed adipose tissue (4/6), at least moderate stromal atypia (4/6), and an elevated mitotic activity ≥3mitotic figures/10 HPF (6/6). The stromal cells were positive for CD10 (4/4), CD34 (4/4), KIT (3/4), and SMA (3/4), and negative for GATA3 (0/6), p63 (0/6), SOX10 (0/6), ER (0/4), PR (0/4), HER2 (0/4), nuclear beta-catenin (0/5), and myogenin (0/4). No patient had a PST recurrence or metastasis (average follow-up of 91 months). Conclusion. We confirm that PST shares morphologic and immunophenotypic similarities with phyllodes tumor (PT). However, PST can be reliably differentiated from PT using the AFIP criteria. Additionally, PST's immunoprofile of positive KIT and CD34 stromal expression alongside the negative GATA3, p63, and SOX10 reactivity can aid the pathologist in excluding metaplastic carcinoma. All 6 of our PST behaved as benign neoplasms akin to benign PT.

[The significance of C-KIT gene mutations in the diagnosis and prognosis of malignant tumors]

Mutations in the C-KIT gene encoding type III receptor tyrosine kinase that regulates cellular processes, such as differentiation, survival, proliferation, migration, and apoptosis, are found in some neoplasms: gastrointestinal stromal tumor, mastocytosis, melanoma, breast carcinomas, myeloid leukemias, and a number of others. Tumors that exhibit these mutations are sensitive to therapy with tyrosine kinase inhibitors, which makes it necessary to correctly identify the mutation status by C-KIT in order to apply a personalized approach to therapy. This literature review shows that the type and localization of the C-KIT gene mutation are of crucial prognostic value and significance in choosing drugs for antitumor therapy, but traditional diagnostic methods fail to determine accurate mutation characteristics. Routine sequencing techniques focus on identifying the gene mutations associated with specific cellular processes, such as DNA damage and repair. The emergence of next-generation sequencing techniques has solved this problem, making it possible to fully analyze the genome of a malignant neoplasm, with constant screening for new mutations that appear as the tumor develops, affect the prognosis of the disease, and change its sensitivity to the antitumor therapy.