Correlation Between Preoperative Radiological and Postoperative Pathological Tumor Size in Patients With HER2+ Breast Cancer After Neoadjuvant Chemotherapy Plus Trastuzumab and Pertuzumab

BACKGROUND

Neoadjuvant chemotherapy (NAC) in combination with anti-HER2 treatment is standard of care in patients with early HER2 positive breast cancer. Preoperative radiological evaluation is mandatory for defining the extent of surgery. In this study, we evaluated the correlation between preoperative radiological and postoperative pathological tumor size in early HER2 positive patients after neoadjuvant chemotherapy in combination with trastuzumab and pertuzumab. In a patient population with HER2 positive breast cancer, who received neoadjuvant chemotherapy and anti-HER2 treatment, the correlation between preoperative radiological and postoperative pathological tumor size was performed. Concordance of radiological and pathological tumor size was found in 55.7%, leading to more extensive breast surgery as required in 7 cases and to the underestimation of 6 neoplastic lesions before surgery, respectively.

PATIENTS AND METHODS

Seventy early HER2 positive breast cancer patients were included and retrospectively analysed. All preoperative radiological assessments as well as the tumor board decision on surgical extent and pathological evaluation were completed at the Medical University of Vienna. Preoperative radiological assessment of tumor size and lymph node status were compared with final histopathological findings. The correlation between different radiological modalities regarding tumor size was investigated.

RESULTS

Concordance of radiological and pathological tumor size was found in 55.7 % (50% by sonography and 66.7% by MRI, respectively) of patients with a nonsignificant correlation of r = 0.31 (P = .08). Of the 39 patients with pathologic complete remission (pCR), 16 were also classified as radiological complete response (rCR) while 23 of those showed a radiological stable disease or partial response. In 6 patients, radiological assessment showed a CR but invasive cancer with a tumor size range from 7 to 36 mm was found in histopathological examination. Neither menopausal status (P= .69) nor BMI (P = .60) and age (P = .50) had an impact on the correlation between radiological and histopathological tumor size. Regarding lymph node status, a statistically significant association and clinically relevant correlation between radiological and histopathological evaluation was found (r = 0.66, P < .001).

CONCLUSION

Concordance between radiology and histopathology was low regarding tumor size after NAC in combination with trastuzumab and pertuzumab, but significant regarding lymph node status.

The anti-B7-H4 checkpoint synergizes trastuzumab treatment to promote phagocytosis and eradicate breast cancer

Trastuzumab is a humanized mAb used to treat HER2-overexpressing breast cancer; however its mechanisms remain to be fully elucidated. Previous studies suggest a role for immunity in mediating trastuzumab-specific antitumor effects. This study evaluated the role(s) of trastuzumab and other antibodies on macrophage activation and Ab-dependent cell-mediated phagocytosis (ADCP) of HER2⁺ breast cancer cells in vitro and in vivo. We employed orthotopic implantation of HER2⁺ murine breast cancer (BC) cells in immunocompetent mouse models, a human HER2⁺ BC xenograft in an immune humanized mouse model, and human PDXs involving adoptive transfer of autologous macrophages to simulate an endogenous mammary tumor-immune microenvironment. Our study demonstrated that trastuzumab greatly and consistently increased macrophage frequency and tumor-cell phagocytosis, and that concurrent knockdown of B7-H4 by a neutralizing antibody increased immune cell infiltration and promoted an antitumor phenotype. Furthermore, neoadjuvant trastuzumab therapy significantly upregulated B7-H4 in the cancer-infiltrating macrophages of HER2⁺ BC patients, which predicted poor trastuzumab response. We suggest that strategies to specifically enhance ADCP activity might be critical to overcoming resistance to HER2 mAb therapies by inhibiting tumor growth and potentially enhance antigen presentation. Furthermore, these results advance the understanding of macrophage plasticity by uncovering a dual role for ADCP in macrophages involving elimination of tumors by engulfing cancer cells while causing a concomitant undesired effect by upregulating immunosuppressive checkpoints.

Dissecting Effects of Anti-cancer Drugs and Cancer-Associated Fibroblasts by On-Chip Reconstitution of Immunocompetent Tumor Microenvironments

A major challenge in cancer research is the complexity of the tumor microenvironment, which includes the host immunological setting. Inspired by the emerging technology of organ-on-chip, we achieved 3D co-cultures in microfluidic devices (integrating four cell populations: cancer, immune, endothelial, and fibroblasts) to reconstitute ex vivo a human tumor ecosystem (HER2⁺ breast cancer). We visualized and quantified the complex dynamics of this tumor-on-chip, in the absence or in the presence of the drug trastuzumab (Herceptin), a targeted antibody therapy directed against the HER2 receptor. We uncovered the capacity of the drug trastuzumab to specifically promote long cancer-immune interactions (>50 min), recapitulating an anti-tumoral ADCC (antibody-dependent cell-mediated cytotoxicity) immune response. Cancer-associated fibroblasts (CAFs) antagonized the effects of trastuzumab. These observations constitute a proof of concept that tumors-on-chip are powerful platforms to study ex vivo immunocompetent tumor microenvironments, to characterize ecosystem-level drug responses, and to dissect the roles of stromal components.

Clinicopathologic Factors Associated With Response to Neoadjuvant Anti-HER2-Directed Chemotherapy in HER2-Positive Breast Cancer

BACKGROUND

HER2-targeted neoadjuvant therapy has high efficacy in treating HER2-positive breast cancer. Response to neoadjuvant therapy helps clinicians make treatment decisions and make estimates about prognosis. This study examined clinicopathologic features to determine which may be most predictive of response to neoadjuvant therapy in HER2⁺ breast cancer.

PATIENTS AND METHODS

Patients with HER2⁺ breast cancer (n = 173) who had an initial biopsy performed between 2010 and 2016 were identified at our institution. Tumor response was evaluated on excisional specimens using the MD Anderson residual cancer burden (RCB) classification. Tumors with pathologic complete response (defined as no residual invasive carcinoma in the breast and lymph nodes) and RCB-I were classified as having response and tumors with RCB-II and -III as having no response. Patient age, tumor size, nuclear grade (1/2 vs. 3), mitosis, Nottingham grade, HER2 immunohistochemistry (1/2+ vs. 3+), HER2/CEP17 (chromosome enumeration probe 17) ratio, HER2 copy number, estrogen receptor, progesterone receptor, Ki-67, and tumor-infiltrating lymphocytes (TIL) were evaluated and correlated with response. TILs were evaluated for an average and also for the hot spot/total tumor stromal ratio.

RESULTS

Small tumor size, low estrogen receptor and progesterone receptor expression, HER2 immunohistochemistry 3+, high Ki-67, high HER2/CEP17 ratio, and high HER2 copy number were significantly associated with response (all P < .05). TIL hot spot was associated with RCB in univariate (P < .05) but not multivariate analyses.

CONCLUSION

Clinicopathologic features may help predict HER2⁺ breast cancer response to neoadjuvant therapy. Larger studies would be useful to confirm these associations, which may have relevance to clinical practice.

Recombinant nanocomposites by the clinical drugs of Abraxane® and Herceptin® as sequentially dual-targeting therapeutics for breast cancer

Breast cancer greatly threatens the health of women all over the word despite of several effective drugs. Targeted therapy for breast cancer is limited to human epidermal growth factor receptor 2 (HER2). Herceptin^®, monoclonal antibody against HER2, is now widely used in HER2(+) breast cancer. Abraxane^®, the current gold standard for paclitaxel (PTX) delivery, has shown superiority in breast cancer based on nanoparticle albumin bound technology. Despite these advances, further novel targeted therapy with more improved anti-tumor efficacy for breast cancer is still urgently needed. Here, we report the recombinant nanocomposites (NPs) composed of the above two clinical drugs of Abraxane^® and Herceptin^® (Abra/anti-HER2), which at first migrates to the tumor region through the unique targeting mechanism of human serum albumin (HSA) of Abraxane^®, and sequentially further precisely recognize the HER2(+) breast cancer cells due to Herceptin^®. The Abra/anti-HER2 NPs were fabricated by a “one-step” synthesis using EDC/NHS. In vitro analysis of cell viability, apoptosis and cell cycle revealed that Abra/anti-HER2 NPs showed more anti-tumor efficacy against HER2(+) SK-BR-3 cells than Abraxane^® at equivalent PTX concentration. In addition, in HER2(+) breast cancer xenograft model, Abra/anti-HER2 NPs significantly inhibited tumor growth with less side effects. Moreover, the properties of more precise target and delayed release of PTX were proved by NIRF imaging. Thus, our results indicate that Abra/anti-HER2 NPs could represent a next-generation sequentially dual-targeting therapeutic agent for HER2(+) breast cancer.

Bioorthogonal, two-component delivery systems based on antibody and drug-loaded nanocarriers for enhanced internalization of nanotherapeutics

Nanocarriers play an important role in targeted cancer chemotherapy. The optimal nanocarrier delivery system should provide efficient and highly specific recognition of the target cells and rapid internalization of the therapeutic cargo to reduce systemic toxicity as well as to increase the cytotoxicity to cancer cells. To this end, we developed a two-step, two-component targeted delivery system based on antibody and drug-loaded nanocarrier that uses bioorthogonal click reactions for specific internalization of nanotherapeutics. The pretargeting component, anti-HER2 humanized monoclonal antibody, trastuzumab, functionalized with azide groups labels cancer cells that overexpress HER2 surface receptors. The drug carrier component, dibenzylcyclooctyne substituted albumin conjugated with paclitaxel, reacts specifically with the pretargeting component. These two components form cross-linked clusters on the cell surface, which facilitates the internalization of the complex. This strategy demonstrated substantial cellular internalization of clusters consisted of HER2 receptors, modified trastuzumab and paclitaxel-loaded albumin nanocarriers, and subsequent significant cytotoxicity in HER2-positive BT-474 breast cancer cells. Our results show high efficacy of this strategy for targeted nanotherapeutics. We foresee to broaden the applications of this strategy using agents such as radionuclides, toxins, and interfering RNA.