Age-stratified Assessment of Brain Volumetric Segmentation on the Indian Population Using Quantitative Magnetic Resonance Imaging.

BACKGROUND AND PURPOSE: Automated methods for quantifying brain tissue volumes have gained clinical interest for their objective assessment of neurological diseases. This study aimed to establish reference curves for brain volumes and fractions in the Indian population using Synthetic MRI (SyMRI), a quantitative imaging technique providing multiple contrast-weighted images through fast postprocessing. METHODS: The study included a cohort of 314 healthy individuals aged 15-65 years from multiple hospitals/centers across India. The SyMRI-quantified brain volumes and fractions, including brain parenchymal fraction (BPF), gray matter fraction (GMF), white matter fraction (WMF), and myelin. RESULTS: Normative age-stratified quantification curves were created based on the obtained data. The results showed significant differences in brain volumes between the sexes, but not after normalization by intracranial volume. CONCLUSION: The findings provide normative data for the Indian population and can be used for comparative analysis of brain structure values. Furthermore, our data indicate that the use of fractions rather than absolute volumes in normative curves, such as BPF, GMF, and WMF, can mitigate sex and population differences as they account for individual differences in head size or brain volume.

Expression of HGF, pMet, and pAkt is related to benefit of radiotherapy after breast-conserving surgery: a long-term follow-up of the SweBCG91-RT randomised trial.

Experimental studies suggest that hepatocyte growth factor (HGF) and its transmembrane tyrosine kinase receptor, Met, in part also relying on Akt kinase activity, mediate radioresistance. We investigated the importance of these biomarkers for the risk of ipsilateral breast tumour recurrence (IBTR) after adjuvant radiotherapy (RT) in primary breast cancer. HGF, phosphorylated Met (pMet) and phosphorylated Akt (pAkt) were evaluated immunohistochemically on tissue microarrays from 1004 patients in the SweBCG91-RT trial, which randomly assigned patients to breast-conserving therapy, with or without adjuvant RT. HGF was evaluated in the stroma (HGFstr ); pMet in the membrane (pMetmem ); HGF, pMet and pAkt in the cytoplasm (HGFcyt , pMetcyt , pAktcyt ); and pAkt in the nucleus (pAktnuc ). The prognostic and treatment predictive effects were evaluated to primary endpoint IBTR as first event during the first 5 years. Patients with tumours expressing low levels of HGFcyt and pMetcyt and high levels of pAktnuc derived a larger benefit from RT [hazard ratio (HR): 0.11 (0.037-0.30), 0.066 (0.016-0.28) and 0.094 (0.028-0.31), respectively] compared to patients with high expression of HGFcyt and pMetcyt , and low pAktnuc [HR: 0.36 (0.19-0.67), 0.35 (0.20-0.64) and 0.47 (0.32-0.71), respectively; interaction analyses: P = 0.052, 0.035 and 0.013, respectively]. These differences remained in multivariable analysis when adjusting for patient age, tumour size, histological grade, St Gallen subtype and systemic treatment (interaction analysis, P-values: 0.085, 0.027, and 0.023, respectively). This study suggests that patients with immunohistochemically low HGFcyt , low pMetcyt and high pAktnuc may derive an increased benefit from RT after breast-conserving surgery concerning the risk of developing IBTR.

The effects of PTPN2 loss on cell signalling and clinical outcome in relation to breast cancer subtype.

PURPOSE: The protein tyrosine phosphatase PTPN2 dephosphorylates several tyrosine kinases in cancer-related signalling pathways and is thought to be a tumour suppressor. As PTPN2 is not frequently studied in breast cancer, we aimed to explore the role of PTPN2 and the effects of its loss in breast cancer. METHODS: Protein expression and gene copy number of PTPN2 were analysed in a cohort of pre-menopausal breast cancer patients with immunohistochemistry and droplet digital PCR, respectively. PTPN2 was knocked down in three cell lines, representing different breast cancer subtypes, with siRNA transfection. Several proteins related to PTPN2 were analysed with Western blot. RESULTS: Low PTPN2 protein expression was found in 50.2% of the tumours (110/219), gene copy loss in 15.4% (33/214). Low protein expression was associated with a higher relapse rate in patients with Luminal A and HER2-positive tumours, but not triple-negative tumours. In vitro studies further suggested a subtype-specific role of PTPN2. Knockdown of PTPN2 had no effect on the triple-negative cell line, whilst knockdown in MCF7 inhibited phosphorylation of Met and promoted that of Akt. Knockdown in SKBR3 led to increased Met phosphorylation and decreased Erk phosphorylation as well as EGF-mediated STAT3 activation. CONCLUSION: We confirm previous studies showing that the PTPN2 protein is lost in half of the breast cancer cases and gene deletion occurs in 15-18% of the cases. Furthermore, the results suggest that the role of PTPN2 is subtype-related and should be further investigated to assess how this could affect breast cancer prognosis and treatment response.

ERBB2 and PTPN2 gene copy numbers as prognostic factors in HER2-positive metastatic breast cancer treated with trastuzumab.

Trastuzumab has markedly improved the treatment and long-term prognosis of patients with HER2-positive breast cancer. A frequent clinical challenge in patients with relapsing and/or metastatic disease is de novo or acquired trastuzumab resistance, and to date no predictive biomarkers for palliative trastuzumab have been established. In the present study, the prognostic values of factors involved in the HER2-associated PI3K/Akt signalling pathway were explored. The first 46 consecutive patients treated at the Department of Oncology, Linköping University Hospital between 2000 and 2007 with trastuzumab for HER2-positive metastatic breast cancer were retrospectively included. The gene copy number variation and protein expression of several components of the PI3K/Akt pathway were assessed in the tumour tissue and biopsy samples using droplet digital polymerase chain reaction and immunohistochemistry. Patients with tumours displaying a high-grade ERBB2 (HER2) amplification level of ≥6 copies had a significantly improved overall survival hazard ratio [(HR)=0.4; 95%, confidence interval (CI): 0.2-0.9] and progression-free survival (HR=0.3; 95% CI: 0.1-0.7) compared with patients with tumours harbouring fewer ERBB2 copies. High-grade ERBB2 amplification was significantly associated with the development of central nervous system metastases during palliative treatment. Copy gain (≥3 copies) of the gene encoding the tyrosine phosphatase PTPN2 was associated with a shorter overall survival (HR=2.0; 95% CI: 1.0-4.0) and shorter progression-free survival (HR=2.1; 95% CI: 1.0-4.1). In conclusion, high ERBB2 amplification level is a potential positive prognostic factor in trastuzumab-treated HER2-positive metastatic breast cancer, whereas PTPN2 gain is a potential negative prognostic factor. Further studies are warranted on the role of PTPN2 in HER2 signalling.

PTPN2 deficiency along with activation of nuclear Akt predict endocrine resistance in breast cancer.

PURPOSE: The protein tyrosine phosphatase, non-receptor type 2 (PTNP2) regulates receptor tyrosine kinase signalling, preventing downstream activation of intracellular pathways like the PI3K/Akt pathway. The gene encoding the protein is located on chromosome 18p11; the 18p region is commonly deleted in breast cancer. In this study, we aimed to evaluate PTPN2 protein expression in a large breast cancer cohort, its possible associations to PTPN2 gene copy loss, Akt activation, and the potential use as a clinical marker in breast cancer. METHODS: PTPN2 protein expression was analysed by immunohistochemistry in 664 node-negative breast tumours from patients enrolled in a randomised tamoxifen trial. DNA was available for 146 patients, PTPN2 gene copy number was determined by real-time PCR. RESULTS: PTPN2 gene loss was detected in 17.8% of the tumours. Low PTPN2 protein expression was associated with higher levels of nuclear-activated Akt (pAkt-n). Low PTPN2 as well as the combination variable low PTPN2/high pAkt-n could be used as predictive markers of poor tamoxifen response. CONCLUSION: PTPN2 negatively regulates Akt signalling and loss of PTPN2 protein along with increased pAkt-n is a new potential clinical marker of endocrine treatment efficacy, which may allow for further tailored patient therapies.

Met and its ligand HGF are associated with clinical outcome in breast cancer.

Few biomarkers exist to predict radiotherapy response in breast cancer. In vitro studies suggest a role for Met and its ligand HGF. To study this suggested role, MET and HGF gene copy numbers were determined by droplet digital PCR in tumours from 205 pre-menopausal and 184 post-menopausal patients, both cohorts randomised to receive either chemo- or radiotherapy. MET amplification was found in 8% of the patients in both cohorts and HGF amplification in 7% and 6% of the patients in the pre- and post-menopausal cohort, respectively. Met, phosphorylated Met (pMet), and HGF protein expression was determined by immunohistochemistry in the pre-menopausal cohort. Met, pMet, and HGF was expressed in 33%, 53%, and 49% of the tumours, respectively. MET amplification was associated with increased risk of distant recurrence for patients receiving chemotherapy. For the pre-menopausal patients, expression of cytoplasmic pMet and HGF significantly predicted benefit from radiotherapy in terms of loco-regional recurrence. Similar trends were seen for MET and HGF copy gain. In the post-menopausal cohort, no significant association of benefit from radiotherapy with neither genes nor proteins was found. The present results do not support that inhibition of Met prior to radiotherapy would be favourable for pre-menopausal breast cancer, as previously suggested.

Loss of protein tyrosine phosphatase, non-receptor type 2 is associated with activation of AKT and tamoxifen resistance in breast cancer.

Breast cancer is a heterogeneous disease and new clinical markers are needed to individualise disease management and therapy further. Alterations in the PI3K/AKT pathway, mainly PIK3CA mutations, have been shown frequently especially in the luminal breast cancer subtypes, suggesting a cross-talk between ER and PI3K/AKT. Aberrant PI3K/AKT signalling has been connected to poor response to anti-oestrogen therapies. In vitro studies have shown protein tyrosine phosphatase, non-receptor type 2 (PTPN2) as a previously unknown negative regulator of the PI3K/AKT pathway. Here, we evaluate possible genomic alterations in the PTPN2 gene and its potential as a new prognostic and treatment predictive marker for endocrine therapy benefit in breast cancer. PTPN2 gene copy number was assessed by real-time PCR in 215 tumour samples from a treatment randomised study consisting of postmenopausal patients diagnosed with stage II breast cancer 1976-1990. Corresponding mRNA expression levels of PTPN2 were evaluated in 86 available samples by the same methodology. Gene copy loss of PTPN2 was detected in 16% (34/215) of the tumours and this was significantly correlated with lower levels of PTPN2 mRNA. PTPN2 gene loss and lower mRNA levels were associated with activation of AKT and a poor prognosis. Furthermore, PTPN2 gene loss was a significant predictive marker of poor benefit from tamoxifen treatment. In conclusion, genomic loss of PTPN2 may be a previously unknown mechanism of PI3K/AKT upregulation in breast cancer. PTPN2 status is a potential new clinical marker of endocrine treatment benefit which could guide further individualised therapies in breast cancer.