Triple-Negative Breast Cancer Histological Subtypes with a Favourable Prognosis

Abstract

Triple-negative breast cancers (TNBC), as a group of tumours, have a worse prognosis than stage-matched non-TNBC and lack the benefits of routinely available targeted therapy. However, TNBC is a heterogeneous group of neoplasms, which includes some special type carcinomas with a relatively indolent course. This review on behalf of the European Working Group for Breast Screening Pathology reviews the literature on the special histological types of BC that are reported to have a triple negative phenotype and indolent behaviour. These include adenoid cystic carcinoma of classical type, low-grade adenosquamous carcinoma, fibromatosis-like metaplastic carcinoma, low-grade mucoepidermoid carcinoma, secretory carcinoma, acinic cell carcinoma, and tall cell carcinoma with reversed polarity. The pathological and known molecular features as well as clinical data including treatment and prognosis of these special TNBC subtypes are summarised and it is concluded that many patients with these rare TNBC pure subtypes are unlikely to benefit from systemic chemotherapy. A consensus statement of the working group relating to the multidisciplinary approach and treatment of these rare tumour types concludes the review.

Vav1 Selectively Down-Regulates Akt2 through miR-29b in Certain Breast Tumors with Triple Negative Phenotype

“…Despite the advent of new sequencing technologies and of advanced computing systems allowed to increase the number of data to be used for cataloging, TNBC subtypes identified with the different methods are often overlapped, and however they fail to precisely classify every single tumor [ 38 , 39 ]. This, on one hand, confirms that specific profiles can define the response to therapy and, ultimately, the prognosis of TNBC [ 2 , 4 , 5 ]. On the other hand, it highlights the requiring of an accurate characterization of each tumor to choose the more effective therapeutic strategy.…”

“…In recent years, TNBC was recognized as a heterogeneous group of malignancies, and various molecular and morphological stratification systems have been proposed to reflect its intrinsic variability. At present, molecular and morphological classifications identify TNBCs with distinct biological behaviors resulting in different histopathology, tumor grade and disease progression rate [ 1 , 2 , 3 , 4 , 5 , 6 ]. At variance with other breast tumors, TNBC lacks specific target molecules, and chemotherapy still represents the only effective therapeutic strategy.…”

Non-conventional and Investigational PET Radiotracers for Breast Cancer: A Systematic Review

“…The fourth subtype of BC is represented by basal-like/triple-negative breast cancer (TNBC), characterized by an ER-, PR-, and HER2- arrangement. This subtype, often occurring in younger women, constitutes ~15–20% of BC and is associated with a higher aggressiveness and a worse prognosis than the other molecular subtypes of BC ( 13 ).…”

“…As already mentioned, the histological and molecular classification of BC is mainly based on the expression of ER, PR, HER2, and the proliferation marker Ki-67. ER- or PR-positive BCs are usually characterized by lower aggressiveness and better prognosis than HER2-enriched and triple-negative subtypes ( 12 , 13 ). However, the receptor status of the disease is not always easily identifiable, especially in metastatic patients where secondary lesions may have receptor status different to the primary tumor ( 91 ).…”

Low-Grade Invasive Triple Negative Breast Carcinoma

“…1,2 It occurs in patients with a wide age range (19-88 years old) and frequently presents as a firm palpable mass. 3 Histologically, LGASC demonstrates round or comma-shaped glandular ducts with variable degrees of squamous differentiation infiltrating into the fibrotic stoma. Tumor cells are composed of a mixture of two types of glandular and squamous cells with low grade nuclei.…”