Carboiodanation of Arynes: Organoiodine(III) Compounds as Nucleophilic Organometalloids.

Organic iodine(III) compounds represent the most widely used hypervalent halogen compounds in organic synthesis, where they typically perform the role of an electrophile or oxidant to functionalize electron-rich or -nucleophilic organic compounds. In contrast to this convention, we discovered their unique reactivity as organometallic-like nucleophiles toward arynes. Equipped with diverse transferable ligands and supported by a tethered spectator ligand, the organoiodine(III) compounds undergo addition across the electrophilic C-C triple bond of arynes while retaining the trivalency of the iodine center. This carboiodanation reaction can forge a variety of aryl-alkynyl, aryl-alkenyl, and aryl-(hetero)aryl bonds along with the concurrent formation of an aryl-iodine(III) bond under mild conditions. The newly formed aryl-iodine(III) bond serves as a versatile linchpin for downstream transformations, particularly as an electrophilic reaction site. The amphoteric nature of the iodine(III) group as a metalloid and a leaving group in this sequence enables the flexible and expedient synthesis of extended π-conjugated molecules and privileged biarylphosphine ligands, where all of the iodine(III)-containing compounds can be handled as air- and thermally stable materials.

BRCAness of brain lesions reflects a worse outcome for patients with metastatic breast cancer.

PURPOSE: Breast cancer often metastasizes to the central nervous system. Although the prognosis of brain metastases from breast cancer has been considered poor, and systemic therapy has not contributed to an improved prognosis, newer agents are expected to be more effective. BRCAness is defined as the status of homologous recombination deficiency (HRD) in tumor tissue, regardless of the presence of pathogenic germline BRCA1/2 variants. A study employing next-generation sequencing analysis showed that HRD was found relatively frequently in brain metastases of breast cancer patients. However, there have been no studies evaluating BRCAness in brain metastases of breast cancer with more efficient, rapid, and cost-effective methods. METHODS: We retrospectively investigated 17 brain metastases of breast cancer that were surgically resected at our hospital from January 2007 to December 2022. Of these, samples from 15 patients were evaluable for BRCAness by employing multiplex ligation-dependent probe amplification (MLPA) assay. RESULTS: Of the 15 patients, five patients (33%) had tumors with BRCAness. Clinicopathological factors of patients with brain metastases with BRCAness were not statistically different from those of patients who possessed tumors without BRCAness. Patients with brain metastases with BRCAness had shorter overall survival compared to those without BRCAness (BRCAness, median 15 months (95% CI 2-30) vs. non-BRCAness, median 28.5 months (95% CI 10-60); P = 0.013). CONCLUSION: In this study, we evaluated BRCAness in brain metastases of breast cancer with the MLPA method, and found that about one-third of patients had BRCAness-positive tumors. The analysis of BRCAness using MLPA has the potential for practical clinical use.

Selective induction of thymic stromal lymphopoietin expression by novel nitrogen-containing steroid compounds in PAM-212 cells.

Background: Thymic stromal lymphopoietin (TSLP) has been shown to be able to amplify Tregs. Thus, TSLP induction has the potential to induce endogenous Tregs and control autoimmunity. In the previous research, we found that a new compound named 02F04 can induce TSLP production while simultaneously activating the liver X receptor (LXR). Because LXR activation leads to a decrease in Treg, we attempted to find a 02F04-derivative, druggable lead compound with a basic skeleton that induces TSLP production without activating LXR. As the results, we found HA-7 and HA-19 and, in this study, examined the molecular mechanisms in TSLP production. Methods: A murine keratinocyte cell line PAM 212 was stimulated with HA-7 and HA-19, and then the expressions of cytokines were examined via ELISA and real-time fluorescence quantitative PCR. Results: HA-7 and HA-19 induced TSLP production but almost not the expression of TNF-α, IL-13, IL-25, and IL-33 in PAM212 cells. These compounds inhibited LXR activities. The TSLP expression induced by HA-7 and HA-19 was inhibited by the Gq/11 inhibitor YM-254890, ROCK inhibitor Y-27632, and ERK inhibitor U0126. HA-7 and HA-19 also induced the formation of stress fiber and ERK phosphorylation, which were inhibited by YM-254890 and Y-27632. Conclusions: Our findings indicated that HA-7 and HA-19 selectively induced TSLP production in PAM212 via Gq/11, Rho/ROCK and ERK pathways. Our findings also indicated that TSLP expression was differentially regulated from other cytokines, and the selective expression could be induced with low-molecular-weight compounds such as HA-7 and HA-19.

Clinicopathological Features Related to the Efficacy of CDK4/6 Inhibitor-Based Treatments in Metastatic Breast Cancer.

BACKGROUND: Resistance to endocrine therapy has been a major obstacle in the management of hormone receptor (HR)-positive metastatic breast cancer (MBC). Meanwhile, a number of treatments are available to such patients, and physicians often encounter difficulties in choosing the most appropriate treatments for individual patients. The combination of CDK 4/6 inhibitors (CDKi) and endocrine therapy has now become a standard treatment for HR-positive and human epidermal growth factor receptor 2 (HER2)-negative MBC. However, no predictive markers for CDKi-based treatments have been established. Considering their side effects and the financial burden on patients, identifying such markers is crucial. METHODS: Clinicopathological features of 107 patients with HR-positive HER2-negative MBC, who received CDKi-based treatments at our institution were retrospectively investigated. HR status in distant metastatic lesions and immunocompetent cells in peripheral blood were also studied. RESULTS: Progression-free survival (PFS) was significantly shorter in patients whose primary tumour was high grade (P = 0.016) or high neutrophil-to-lymphocyte ratio (NLR) at baseline (P = 0.017). Meanwhile, there were no differences in other factors, such as expression levels of hormone receptors. Patients whose metastatic lesions were of low tumour grade or high Ki67 labelling index had longer PFS, and such trends were more obvious than primary lesions. CONCLUSION: Our data indicate that tumour grade in primary lesion and NLR are potential predictive factors for CDKi-based treatments. Moreover, pathological assessment of metastatic lesions might also be useful.

Clinicopathological Examination of Metaplastic Spindle Cell Carcinoma of the Breast: Case Series.

BACKGROUND: Spindle cell carcinoma (SpCC) of the breast is a rare histological type, a subtype of metaplastic carcinoma characterized by atypical spindle cell and epithelial carcinoma. The proportions of the spindle cell and epithelial components vary among tumours. Due to its rarity, biological characteristics of this disease have been poorly studied. METHODS: In total, 10 patients with SpCC were surgically treated at our institution from January 2007 to December 2018. We retrospectively investigated these SpCC cases, focusing on the differences between spindle cell and epithelial components. Microsatellite status was also examined. RESULTS: Nine cases were triple-negative breast cancer (TNBC). The rates of high tumour grade were 70% in spindle cell components and 56% in epithelial components (P = .65), while the mean Ki67 labelling index were 63% and 58%, respectively (P = .71). Mean programmed death ligand 1 (PD-L1) expression in these components was 11% and 1%, respectively (P = .20). All 10 tumours were microsatellite stable. Patient outcomes of triple-negative SpCC did not differ from those of propensity-matched patients with conventional TNBC. CONCLUSIONS: Spindle cell components showed higher values in factors examined, although there was no statistically significant difference. Our data reveal that these 2 components of SpCC may be of different biological nature.

Cerebral hemorrhage due to amyloid angiopathy that was difficult to differentiate from breast cancer metastasis: a case report.

BACKGROUND: Breast cancer patients are known to develop brain metastasis at a relatively high frequency. However, imaging findings of brain metastases vary, and it is sometimes very difficult to distinguish these from other tumorous lesions and non-neoplastic lesions, such as cerebral hemorrhage. Meanwhile, there are various causes of cerebral hemorrhage; a major one is cerebral amyloid angiopathy (CAA). With the advancement of imaging technology, CAA-related cerebral hemorrhage can be more precisely diagnosed with magnetic resonance imaging (MRI), but definitive diagnosis of CAA can only be made based on pathological assessment. Herein, we report a case of consciousness disorder appearing during adjuvant therapy for breast cancer. We initially considered that the patient's cerebral hemorrhage was due to a metastatic tumor, but based on excisional biopsy, she was diagnosed with CAA. CASE PRESENTATION: A 73-year-old Japanese woman underwent curative surgery for left breast cancer. Her disease was hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-positive invasive ductal carcinoma (pStage IIB). While receiving adjuvant treatment, she developed disorientation, and emergent imaging revealed multiple cerebral hemorrhages. There was no apparent enhancement in the cerebral parenchyma on MRI, and differential diagnosis included hemorrhage due to a metastatic tumor, intravascular large B-cell lymphoma, CAA and thrombotic intracranial bleeding. After hospitalization, the bleeding lesion enlarged, resulting in cerebral hernia, and she needed emergency drainage surgery. The tissue surrounding the hemorrhage was pathologically assessed, and she was diagnosed with CAA. Although we initially suspected the lesion to be a metastatic tumor from breast cancer, there were no tumorous cells. CONCLUSION: Atypical MRI findings made diagnosis difficult in this case, but it should be considered for differential diagnosis when multiple cerebral hemorrhages in elderly patients are observed, especially in cases with symptoms such as transient multifocal neurological deficits and dementia.

Glycans unique to the relapse-prone subset within triple-negative breast cancer as revealed by lectin array-based analysis of surgical specimens.

INTRODUCTION: Molecular and cellular characteristics of the relapse-prone subset within triple-negative breast cancer (TNBC) remain unclear. Aberrant glycosylation is involved in the malignant behavior of cancer cells. In the present study, we aimed to reveal glycan profiles unique to relapsed TNBC patients. METHODS: Thirty TNBC patients who did not undergo neoadjuvant chemotherapy but postoperative standard adjuvant therapy from 2009 through 2016 at Juntendo Hospital were investigated. TNBC cells were resected from primary breast cancer sections of formalin-fixed surgical specimens using laser-assisted microdissection. The binding intensities of the extracted glycoproteins to 45 lectins were quantified using lectin microarray and compared between relapsed and non-relapsed patients. Immunohistochemical staining with TJA-II lectin in specimen sections was performed. RESULTS: Five patients relapsed during the follow-up (range 37-123 months). Lectin microarray analysis revealed that 7 out of 45 lectins showed significant differences in binding intensity between the relapsed and the non-relapsed group. TJA-II, ACA, WFA, and BPL showed stronger binding in the relapsed group. PNGase F treatment of TNBC cell lysates suggested that TJA-II and ACA bind O-glycans. TJA-II staining of tissue sections revealed strong binding to cell surface membranes and to the cytoplasm of TNBC cells, but not to other types of cells. Significantly more TNBC cells were stained in tissue sections from relapsed than non-relapsed patients. CONCLUSIONS: TNBC cells from relapsed patients showed a unique lectin reactivity, with higher levels of TJA-II (also WFA and BPL) binding than in non-relapsed patients. The results are potentially useful to develop new prognostic and therapeutic tools.

Molecular Characteristics of Lymphocyte-predominant Triple-negative Breast Cancer.

BACKGROUND/AIM: Tumor-infiltrating lymphocytes (TILs) are considered a prognostic marker for triple-negative breast cancer (TNBC). Immune checkpoint inhibitor (ICI)-based treatments are more effective for tumors with PD-L1-positive TILs, suggesting crucial roles of TILs in the local tumor immunity. However, factors attracting TILs are still largely unknown. Focusing on tumor antigenicity, we examined TNBC samples to identify the characteristics of TIL-high tumors. PATIENTS AND METHODS: Nine treatment-naïve TNBCs (TIL-high: five, TIL-low: four) were subjected to next-generation sequencing (NGS). Loss of heterozygosity (LOH) of PTEN was also analyzed. RESULTS: A variety of copy number variations were observed, and no genes differed significantly between TIL-high and -low groups. However, PTEN loss was more frequently observed in the TIL-high group: 60% compared to 25% in TIL-low tumors. NGS correlated well with LOH analysis in identifying PTEN loss. All three tumors with PTEN loss in the TIL-high group showed high PD-L1. All nine samples were microsatellite-stable. CONCLUSION: Frequent PTEN loss and high expression of PD-L1 in TIL-high TNBC suggest that PTEN mutation may be a biomarker for ICIs.

Biological and Clinicopathological Implications of Beta-3-N-acetylglucosaminyltransferase 8 in Triple-negative Breast Cancer.

BACKGROUND/AIM: Triple-negative breast cancer (TNBC) remains difficult to treat and new molecular targets are needed. Here, we investigated the impact of glycosyltransferase genes on TNBC patient survival. PATIENTS AND METHODS: mRNA expression levels of 101 glycosyltransferase genes in TNBC patients were compared for correlation with patient survival using The Cancer Genome Atlas data. An antibody to ß-3-N-acetylgluco-saminyltransferase 8 (B3GNT8) was applied to investigate B3GNT8 protein distribution and expression levels in 23 TNBC surgical specimens. RESULTS: B3GNT8 mRNA levels inversely correlated with relapse-free survival (p<0.01) and overall survival (p<0.05) in TNBC patients. Anti-B3GNT8 antibody binding was observed as dots in the cytoplasm of cancer cells. These dots were supposed to correspond to B3GNT8 protein in tumour cells, but their number was smaller in relapsed patients than in non-relapsed patients. CONCLUSION: B3GNT8 mRNA expression levels in TNBC tumour tissues are potentially useful in distinguishing patients with favourable and poor clinical outcomes.

Microsatellite instability and mismatch repair protein expressions in lymphocyte-predominant breast cancer.

The frequency of microsatellite instability (MSI) is reportedly extremely low in breast cancer, despite widespread clinical expectations that many patients would be responsive to immune-checkpoint inhibitors (ICI). Considering that some triple-negative breast cancers (TNBC) responded well to ICI in a clinical trial and that a high density of tumor-infiltrating lymphocytes (TILs) is frequently observed in other cancers with high levels of microsatellite instability (MSI-H), we hypothesized that some TNBC with a high density of TILs would be MSI-H. Medullary carcinoma (MedCa) of the breast, a rare histological type, is characterized by a high density of TILs. Considering that MedCa of the colon is often MSI-H, we suspected that MedCa in breast cancer might also include MSI-H tumors. Therefore, we conducted MSI tests on such breast cancers with a high density of TILs. The MSI status of 63 TIL-high TNBC and 38 MedCa tumors, all from Asian women who had undergone curative surgery, were determined retrospectively. DNA mismatch repair (MMR) proteins and PD-L1 expression were also investigated immunohistochemically. All samples were microsatellite stable, being negative for all microsatellite markers. TIL-high TNBC with low MLH1 protein had higher levels of PD-L1 in stromal immune cells (P = .041). MedCa tumors showed significantly higher PD-L1 expression in immune cells than in TIL-high TNBC (<.001). We found that MSI-H tumors were absent in TIL-high breast cancers. Examination of MMR proteins, not a purpose of Lynch syndrome screening, may merit further studies to yield predictive information for identifying patients who are likely to benefit from ICI.

Neutrophil-to-lymphocyte ratio and histological type might predict clinical responses to eriburin-based treatment in patients with metastatic breast cancer.

BACKGROUND: Metastatic breast cancer (MBC) is generally considered to be incurable. Although many options are available for treating MBC, physicians often encounter difficulties in choosing the most appropriate treatment because the MBCs of individual patients respond differently even to the same treatments. Thus, predictive markers for therapeutic efficacy are urgently needed. Neutrophil- and platelet-to-lymphocyte ratios (NLR and PLR, respectively), have been studied and established as prognostic markers for breast cancer patients but whether either or both of these markers are predictive of treatment responses is still unclear. Herein, we investigated predictive markers for eribulin-based treatment responsiveness in patients with MBC, by examining clinicopathological features, including several markers of immunocompetent cells in peripheral blood. METHODS: Clinicopathological features of the 104 patients with metastatic/Stage IV breast cancer given eribulin-based regimens were investigated in relation to clinical responses to eribulin-based treatments and progression-free-survival (PFS). RESULTS: Special histological types and high NLR at baseline were independently related to poor clinical responses to the treatments (p = 0.023 and 0.039, respectively). The Cox hazard model revealed that patients with oestrogen receptor (ER)-negative tumours and high NLR, monocyte-to-lymphocyte ratio (MLR) and PLR showed significantly shorter PFS (p = 0.021, 0.005, 0.008 and 0.030, respectively). On multivariate analysis, only ER status and NLR remained independent factors related to PFS (p = 0.011 and 0.003, respectively). CONCLUSIONS: Our data revealed that special histological types and high NLR might be factors related to low responsiveness to eribulin-based regimens in patients with MBC.

Factors Affecting Decisions Regarding Terminal Care Locations of Patients With Metastatic Breast Cancer.

BACKGROUND: Metastatic breast cancer (MBC) is generally incurable, but patients can survive longer than those with other cancer types. Treatment strategies for MBC are complex, and it is difficult to establish evidence of efficacy since symptoms and patient backgrounds vary markedly. Some patients struggle to decide where to receive end-of-life care, despite palliative care intervention, and some die in unexpected places. With the aim of ascertaining the best way to intervene on behalf of patients with end-stage breast cancer, we retrospectively examined interventions provided by our palliative care team. We investigated factors influencing the decision-making processes of patients with MBC regarding end-of-life care locations and where patients actually died. METHODS: Clinical records of 44 patients with MBC, all Japanese women, who received palliative care interventions at our hospital, were retrospectively investigated. We examined factors, such as age, possibly impacting decision-making processes regarding the final location and actual place of death. RESULTS: Thirty-five (80%) patients were able to decide where to receive end-of-life care, while the others were not. For these 35 patients, desired locations were the palliative care unit (77%), home palliative care (14%), and the hospital (9%). Age and recurrence-free survival (RFS) were factors influencing patients' decision-making processes (P = .030 and .044, respectively). Of the 35 patients, 25 (71%) were able to receive end-of-life care at their desired locations. CONCLUSIONS: Young patients and those with short RFS struggled with making decisions regarding where to receive end-of-life care. Such patients might benefit from prompt introduction of advanced care planning.

Impact of circulating tumour cells on survival of eribulin-treated patients with metastatic breast cancer.

Several clinical studies have examined circulating tumour cells (CTCs). However, the application of CTCs as a predictive/prognostic marker for breast cancer patients has yet to be established, particularly the selection of suitable markers for detecting CTCs. We recently investigated CTCs, including mesenchymal status, from metastatic breast cancer patients who had received eribulin-based treatment. We found that assessment of both mesenchymal and epithelial CTCs might be important for predicting eribulin responsiveness. In the current study, we followed up the outcomes of these patients after eribulin treatment and investigated the possibility of CTC analysis results serving as prognostic markers for this patient population. Twenty-one patients were enrolled and peripheral blood samples were collected before eribulin-based treatments. CTCs were then examined using a Microfluidic Chip device. CTCs positive for vimentin and pan-cytokeratin were defined as mesenchymal and epithelial CTCs, respectively. Overall survival (OS) was assessed in relation to the number of CTCs and clinicopathological factors. During the observation period, 13 patients (62%) died due to breast cancer and the median OS was 18 months. Patients with high-grade tumours and a high total number of CTCs showed significantly shorter OS than those with low-grade tumours and smaller CTC burdens (p = 0.026 and 0.037, respectively). Patients who received eribulin as the first chemotherapy for metastatic disease showed longer OS (p = 0.006). Our data suggest that determining numbers of both mesenchymal and epithelial CTCs might predict survival for patients receiving eribulin.

Targeting PKCδ as a Therapeutic Strategy against Heterogeneous Mechanisms of EGFR Inhibitor Resistance in EGFR-Mutant Lung Cancer.

Multiple mechanisms of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been identified in EGFR-mutant non-small cell lung cancer (NSCLC); however, recurrent resistance to EGFR TKIs due to the heterogeneous mechanisms underlying resistance within a single patient remains a major challenge in the clinic. Here, we report a role of nuclear protein kinase Cδ (PKCδ) as a common axis across multiple known TKI-resistance mechanisms. Specifically, we demonstrate that TKI-inactivated EGFR dimerizes with other membrane receptors implicated in TKI resistance to promote PKCδ nuclear translocation. Moreover, the level of nuclear PKCδ is associated with TKI response in patients. The combined inhibition of PKCδ and EGFR induces marked regression of resistant NSCLC tumors with EGFR mutations.

Analysis of circulating tumour cell and the epithelial mesenchymal transition (EMT) status during eribulin-based treatment in 22 patients with metastatic breast cancer: a pilot study.

BACKGROUND: Liquid biopsy approaches, such as measuring circulating tumour cells (CTCs), have recently been introduced in several clinical studies. However, the development of CTCs as a predictive marker for treatment effects on breast cancer remains an enormous task. We investigated CTCs, including epithelial mesenchymal transition (EMT) status, from metastatic breast cancer patients who had received eribulin-based treatment, which reportedly suppresses EMT as a means of tumour suppression. Our aim was to test the possibility of this method serving as a tool predicting eribulin efficacy. METHODS: Twenty-two patients were enrolled and peripheral blood samples were collected before eribulin treatment. CTCs were then examined using a Microfluidic Chip device. CTCs positive for vimentin and pan-cytokeratin were defined as mesenchymal and epithelial CTCs, respectively. Progression-free survival (PFS) and clinical response were assessable in 20 and 18 patients, respectively, in relation to the number of CTCs. RESULTS: Numbers of total CTCs were significantly increased in patients with progressive disease during treatment (p = 0.006). Median PFS was 14.6 weeks and patients with more total and mesenchymal CTCs at baseline had significantly shorter PFS (p = 0.0013 and 0.013, respectively). Multivariate logistic regression analysis revealed small number of total baseline CTCs and long disease-free survival to be related to long PFS (p = 0.0004 and 0.020, respectively). CONCLUSIONS: Our data suggest that determining both mesenchymal and epithelial CTCs at baseline might be a good tool for predicting eribulin responsiveness. Evaluation of mesenchymal CTC can be considered as a parameter in larger studies, while most clinical trials are currently employing only the detection of the epithelial cellular adhesion molecule (EpCAM).

The role of PRMT1 in EGFR methylation and signaling in MDA-MB-468 triple-negative breast cancer cells.

BACKGROUND: Epidermal growth factor receptor (EGFR) is often overexpressed in triple-negative breast cancer (TNBC). However, clinical studies have shown that therapies against EGFR are not effective in patients with TNBC. Recently, it has been reported that arginine 198/200 in EGFR extracellular domain is methylated by PRMT1 and that the methylation confers resistance to EGFR monoclonal antibody cetuximab in colorectal cancer cells. To explore a potential mechanism underlying intrinsic resistance to anti-EGFR therapy in TNBC, we investigated the role of PRMT1 in EGFR methylation and signaling in MDA-MB-468 (468) TNBC cells. METHODS: We knocked down PRMT1 in 468 cells by shRNA, and subjected the cell lysates to Western blot analysis to examine EGFR activation and its downstream molecules. We also evaluated cell proliferation and sphere formation of PRMT1-knockdown cells. Finally, we examined the effects of pan-PRMT inhibitor, AMI-1, on cetuximab by colony formation and soft agar assays. RESULTS: EGFR methylation and activity was significantly reduced in PRMT1-knockdown cells compared to the parental cells. Knockdown of PRMT1 also reduced cell proliferation and sphere formation. Moreover, AMI-1 sensitized 468 cells to cetuximab. CONCLUSION: The results indicate that PRMT1 is critical for EGFR activity in 468 cells. Our data also suggest that inhibition of PRMT1 sensitizes TNBC cells to cetuximab. Thus, inhibition of PRMT1 may be an effective therapeutic strategy to overcome intrinsic resistance to cetuximab in TNBC.

Differences in Ki67 expressions between pre- and post-neoadjuvant chemotherapy specimens might predict early recurrence of breast cancer.

The prognosis of breast cancer patients not obtaining a pathological complete response (pCR) with neoadjuvant chemotherapy (NAC) is poorer than that of pCR patients. Identifying new prognostic factors for non-pCR patients is important because fractions of this population might benefit from novel adjuvant treatments currently under development. High Ki67 expression in remnant disease after NAC has been described as a poor prognostic factor. Studies have shown that a reduction in Ki67 expression is more often observed in good responders to chemotherapy. We hypothesized that the change in Ki67 expression might be useful for predicting patient outcomes and thus retrospectively examined pairs of biopsy and surgical specimens of breast tissue from individual patients. One hundred sixteen patients with remnant invasive disease in the breast, who received NAC and underwent surgery at our institution, were retrospectively examined. Differences in Ki67 expression between pre- and post-NAC specimens were analyzed in relation to patient outcomes. The mean Ki67 expression value after NAC was higher in patients who developed metastasis than in those without metastasis (P<.01). Tumors showing higher Ki67 expression in the surgical than in the biopsy specimen were more frequent in patients with metastasis (P<.01). This trend was more obvious in patients who developed metastasis within 1 year after surgery. Our results indicate that a difference in Ki67 expressions after versus before NAC might be an important predictor of early metastasis. Evaluating not only absolute Ki67 values, but also any changes in response to NAC, may improve the prediction of patient outcomes.

A perspective on anti-EGFR therapies targeting triple-negative breast cancer.

Triple-negative breast cancer (TNBC), which lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), accounts for about 15-20% of breast cancers and is the most aggressive breast cancer subtype. There are currently no effective therapies against metastatic TNBC. Compared with other breast cancer subtypes, EGFR is frequently overexpressed in TNBC and a potential therapeutic target for this disease. There are two types of EGFR inhibitors, small molecular tyrosine kinase inhibitor (TKI) and monoclonal antibody (mAb), for the treatment of cancers, such as non-small cell lung cancer and colorectal cancer. For breast cancer, however, the clinical trials of EGFR inhibitors have failed due to low response rates. Because a small portion of patients do demonstrate response to EGFR inhibitors, it may be necessary to stratify patients to enhance the efficacy of EGFR inhibitors in TNBC and to develop the effective combination therapy for this patient population. In this review, we describe some of the molecular mechanisms underlying EGFR inhibitor sensitivity and further discuss the possible therapeutic strategies to increase the efficacy of EGFR inhibitors in TNBC.

Blocking c-Met-mediated PARP1 phosphorylation enhances anti-tumor effects of PARP inhibitors.

Poly (ADP-ribose) polymerase (PARP) inhibitors have emerged as promising therapeutics for many diseases, including cancer, in clinical trials. One PARP inhibitor, olaparib (Lynparza, AstraZeneca), was recently approved by the FDA to treat ovarian cancer with mutations in BRCA genes. BRCA1 and BRCA2 have essential roles in repairing DNA double-strand breaks, and a deficiency of BRCA proteins sensitizes cancer cells to PARP inhibition. Here we show that the receptor tyrosine kinase c-Met associates with and phosphorylates PARP1 at Tyr907 (PARP1 pTyr907 or pY907). PARP1 pY907 increases PARP1 enzymatic activity and reduces binding to a PARP inhibitor, thereby rendering cancer cells resistant to PARP inhibition. The combination of c-Met and PARP1 inhibitors synergized to suppress the growth of breast cancer cells in vitro and xenograft tumor models, and we observed similar synergistic effects in a lung cancer xenograft tumor model. These results suggest that the abundance of PARP1 pY907 may predict tumor resistance to PARP inhibitors, and that treatment with a combination of c-Met and PARP inhibitors may benefit patients whose tumors show high c-Met expression and who do not respond to PARP inhibition alone.