Predictive Potential of RNA Polymerase B (II) Subunit 1 (RPB1) Cytoplasmic Aggregation for Neoadjuvant Chemotherapy Failure

We aimed to investigate the contribution of co-translational protein aggregation to the chemotherapy resistance of tumor cells. Increased co-translational protein aggregation reflects altered translation regulation that may have the potential to buffer transcription under genotoxic stress. As an indicator for such an event, we followed the cytoplasmic aggregation of RPB1, the aggregation-prone largest subunit of RNA polymerase II, in biopsy samples taken from patients with invasive carcinoma of no special type. RPB1 frequently aggregates co-translationally in the absence of proper HSP90 chaperone function or in ribosome mutant cells as revealed formerly in yeast. We found that cytoplasmic foci of RPB1 occur in larger sizes in tumors that showed no regression after therapy. Based on these results, we propose that monitoring the cytoplasmic aggregation of RPB1 may be suitable for determining-from biopsy samples taken before treatment-the effectiveness of neoadjuvant chemotherapy.

Perineural Invasion Predicts Unfavorable Prognosis in Patients With Invasive Breast Cancer

BACKGROUND/AIM

Perineural invasion (PNI) is a poor prognostic factor in a variety of cancers. However, the frequency of PNI in invasive breast carcinoma varies among studies, and the prognostic significance of PNI remains unclear. Therefore, we aimed to explore the prognostic value of PNI in breast cancer patients.

PATIENTS AND METHODS

The cohort included 191 consecutive female patients who underwent surgical resection of invasive carcinoma of no special type (NOS). The correlations between PNI and clinicopathological characteristics including prognosis were investigated.

RESULTS

The frequency of PNI was 14.1% (27/191) and the PNI-positive status was significantly correlated with large pathological tumor size (p=0.005), lymph node metastasis (p=0.001), and lymphatic invasion (p=0.009). The log-rank test showed that PNI-positive patients had shorter distant metastasis-free survival (DMFS) (p=0.002) and disease-specific survival (DSS) (p<0.001). According to the multivariate analysis, PNI had a significant adverse effect on DMFS (p=0.037) and DSS (p=0.003).

CONCLUSION

PNI could be used as an independent poor prognostic indicator in patients with invasive breast carcinoma.

Cytokines in various molecular subtypes of breast cancer

INTRODUCTION

Breast cancer is a heterogeneous disease that has multiple molecular and morphological subtypes. Nonetheless, the relation between various molecular subtypes and functional characteristics of a tumor in terms of cytokine secretion remains unknown.

METHODS

We studied spontaneous and mitogen-induced cytokine secretion by invasive breast carcinoma of no special type (IBC NST; cultured tumors and cultured peripheral blood cells), depending on a molecular tumor subtype (where "mitogens" means "polyclonal activators" (PA): phytohemagglutinin p, phytohemagglutinin M, concanavalin A, and Escherichia coli lipopolysaccharide). Enzyme-linked immunosorbent assays were used to determine concentrations of IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1Ra, TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF, and MCP-1 in culture supernatants of the tumors and peripheral blood cells.

RESULTS

The luminal B HER2-positive molecular subtype of IBC NST was found to feature the highest spontaneous secretion of IL-6 and IL-8 and the highest mitogen-induced secretion of IL-6, IL-8, IL-1Ra, and TNF-α by tumors; the highest mitogen-induced secretion of IL-2, IL-6, IL-8, IL-1β, TNF-α, IFN-γ, and G-CSF by peripheral blood cells; and the highest cytokine-producing potential (the ratio of mitogen-induced to spontaneous secretion) of peripheral blood cells for the secretion of IL-6, IL-8, and IL-1Ra as compared to other molecular subtypes. The triple-negative subtype of IBC NST was characterized by the lowest cytokine-producing potential of tumors for the secretion of IL-6 and IL-8 as compared to other molecular subtypes as well as a lower "stimulation index of polyclonal activators" (calculated as (cytokine secretion after incubation with PA)/(spontaneous cytokine secretion)) for IL-18 secretion as compared to luminal subtypes. The XYZ correlated with a suppressive effect of PA on cytokine secretion by tumors of the triple-negative molecular subtype.

CONCLUSION

Therefore, our findings indicate that in IBC NST of luminal B HER2-positive and triple-negative molecular subtypes, the cytokine network has distinctive functional features.