Downregulation of DNAJC12 Expression Predicts Worse Survival for ER-Positive Breast Cancer Patients

Abstract

Background: DNAJC12 (DnaJ heat shock protein family (Hsp40) member C12) encodes a member of the molecular chaperone Hsp40/DnaJ family, which are important protein folding and proteostasis regulators. Its role as a biomarker has been studied for a limited number of cancer types. Objectives: Here, we sought to investigate the potential of DNAJC12 mRNA and protein expression as a prognostic and predictive biomarker for breast cancer (BC).

Methods: Using in silico analysis and data from immunohistochemistry analysis (IHC) of 292 samples from patients with primary BC, we determined the expression pattern and prognostic value of DNAJC12 mRNA and protein expression.

Results: From online publicly available data, we were able to identify the transcripts of DNAJC12 as differentially expressed in patients with different clinicopathological characteristics, such as ER status (P < .001), PR status (P < .001), HER2 status (P < .010) and molecular subtype (P ⩽ .001). We also found DNAJC12 to be a potential prognostic predictor for overall survival, disease-free survival, and responsiveness to treatment; a low DNAJC12 mRNA expression is commonly associated with a worse prognosis. Using IHC analysis, we showed that low DNAJC12 protein-level expression is also associated with a worse prognosis in patients with all subtypes of BC and patients with Luminal BC, and its expression is significantly different between patients with different tumor size classifications (T1/T2 vs T3/T4; P = .013) or with different lymph node involvement (N0 vs N+; P = .005).

Conclusion: Our findings suggested a potential role for DNAJC12 as a prognostic and predictive biomarker for BC.

Keywords: Breast cancer; DNAJC12; biomarker; estrogen receptor; prognosis.

Figure 1.

Study flowchart. The analysis of DNAJC12 expression was performed through data mining using public databases containing mRNA expression data (https://ualcan.path.uab.edu/; https://www.cbioportal.org/; https://www.kmplot.com/; https://rocplot.org/) and by immunohistochemistry (IHC) on tissue microarrays (TMA) containing 292 primary breast tumors.

Figure 2.

DNAJC12 expression pattern and association with prognosis and treatment response. (A) TCGA data analysis in breast cancer samples in comparison to normal samples (a) or among molecular subtypes (b) using the UALCAN portal (https://ualcan.path.uab.edu/). (B) Impact of DNAJC12 expression in long term survival of breast cancer patients (a, b) and in each intrinsic molecular subtypes luminal A (c, d), luminal B (e, f), HER 2 (g, h) and basal-like (i, j). Kaplan-Meier curves of relapse-free survival (a, c, e, g, i) and overall survival (b, d, f, h, j) according to DNAJC12 expression using probe set 223722_at at KM Plotter online tool (https://www.kmplot.com/). (C) Association of DNAJC12 expression with response to endocrine therapy (a) anti-HER2 therapy (b) chemotherapy (c) (https://rocplot.org/).

Figure 3.

DNAJC12 immunostaining in breast cancer primary tumor samples. Representation of the 4 DNAJC12 cytoplasmic staining intensities (A) low and (B) high. Image magnification is described in the figure.

Figure 4.

Breast cancer survival analysis according to DNAJC12 protein expression. Patients were categorized in accordance with the median H-score value after digital analysis of IHC against DNAJC12 by using QuPath software. Kaplan-Meier survival curves of disease-free (A and C) and overall (B and D). Upper curves correspond to all breast cancer cohort and lower curves, to luminal breast cancer cases.

Figure 5.

Breast cancer survival analysis according to estrogen receptor status alone or in combination with DNAJC12 protein expression. Patients were categorized in accordance with estrogen receptor (ER, A, and B) the median H-score value after digital analysis of IHC against DNAJC12 by using QuPath software. Kaplan-Meier survival curves of disease-free (A and C) and overall (B and D). Upper curves correspond to all breast cancer cohort and lower curves, to luminal breast cancer cases.