Correlation between postoperative treatment selection and prognosis determined using the Oncotype DX® test data: a retrospective multicenter study in Japan.

PURPOSE: Oncotype DX® is a frequently used multigene assay for hormone receptor-positive breast cancers. However, limited evidence is available regarding its application in Japan owing to the lack of insurance coverage. Therefore, we conducted this large-scale, retrospective study by collecting data from nine Japanese institutes and assessed postoperative treatment choice and prognosis by using Oncotype DX®. METHODS: Six hundred thirty-two patients who underwent breast surgery and whose recurrence score (RS) data were available were included. They were divided into RS 0-25 and RS ≥ 26 groups. The groups were compared in terms of clinicopathological factors, treatment options, and prognosis. RESULTS: After the median follow-up period of 10.1 years, the disease-free survival (DFS) rates were significantly better in the RS 0-25 group (p = 0.02). Per the recurrent event type, there was no significant intergroup difference in locoregional recurrence (p = 0.139). However, a trend toward better distant DFS was observed in the RS 0-25 group (p = 0.08). Overall survival was also significantly better in this group (p = 0.027). Considering chemotherapy use, DFS worsened among chemotherapy-treated patients with an RS of 0-25 and those with an RS ≥ 26 who did not receive chemotherapy (p < 0.001). Seven (1.35%) chemotherapy-treated patients with an RS of 0-25 showed disease recurrence. CONCLUSIONS: This study presents the largest database-derived prognostic data in Japanese patients, utilizing the Oncotype DX® treatment selection. Further studies are needed to determine the impact on treatment choice, considering the clinical risk, and the need for additional postoperative treatment.

Clinicopathological Characteristics and Prognosis of Triple-Negative Apocrine Carcinoma: A Case-Control Study.

Background: With a prevalence of only 1% among all breast cancers in Japan, apocrine carcinoma (AC) is a rare type of breast cancer, and its clinicopathological characteristics remain unclear. The aim of this study was to evaluate the characteristics and prognosis of AC, in relation to the presence or absence of androgen receptor (AR). Methods: We conducted a retrospective multi-center case-control study (Yokohama Clinical Oncology Group (YCOG): YCOG1701 study) in Japan. A total of 53 patients were registered who were diagnosed with AC between 2000 and 2017 in YCOG-affiliated hospitals. Results: The median age of the patients was 67 (43 - 94) years, and the median observation time was 6.1 years. Among the 53 cases, 24 had triple-negative pure AC (TN-PAC; AR-positive), whereas 29 had other types of AC (other-AC; estrogen receptor-positive and/or human epidermal growth factor receptor 2-positive or AR-negative). Tumor size was smaller (1.4 vs. 2.1 cm, P = 0.024) and metastasis occurred in fewer nodes (12.5% vs. 37.9%, P = 0.036) in the TN-PAC group than in the other-AC group. The number of patients who were administered perioperative adjuvant chemotherapy did not significantly differ between the two groups (TN-PAC/other-AC = 50.0%/55.2%, P = 0.525); however, there was no recurrence in the TN-PAC group, compared to five cases with relapse in the other-AC group. Conclusions: AR-positive AC patients showed a favorable prognosis without adjuvant chemotherapy, even with the TN subtype. A clinical trial exploring the possibility of treatment de-escalation is anticipated.

Accelerated glycolysis in tumor microenvironment is associated with worse survival in triple-negative but not consistently with ER+/HER2- breast cancer.

Metabolic reprogramming to sustain immortality is a hallmark of cancer and glycolysis is an important way to attain this. Thus, we investigate the association of glycolysis and associated pathways in the survival of breast cancer. A total of 5,176 breast cancer patients from multiple independent cohorts were analyzed. We determined the glycolytic signaling score by the degree of enrichment by Gene Set Variant Analysis and the median was used to divide each cohort into high vs low score groups. Glycolysis high breast cancer significantly enriched the hallmark cell proliferation-related gene sets (E2F targets, G2M checkpoint, and MYC targets v1 and v2) and was associated with high MKI67 expression. In all cohorts, triple-negative breast cancer (TNBC) was associated with the highest glycolysis score. It was found that in TNBC, glycolysis high breast cancer was associated with worse survival but in ER-positive/HER2-negative breast cancer this was not observed consistently. The glycolysis high TNBC enriched multiple pro-cancerous gene sets and was infiltrated with a low level of B-cells and anti-cancerous immune cells, and significantly associated with a decreased level of cytolytic activity. It was also observed that the glycolysis was higher in the metastatic sites than in the primary breast cancer and the survival was not affected by the metastatic sites. In conclusion, accelerated glycolysis is associated with cancer cell proliferation and worse survival in TNBC.

High miR-99b expression is associated with cell proliferation and worse patient outcomes in breast cancer.

Although miR-99b is a known suppressive microRNA (miRNA) in several cancers, its role in breast cancer has not been elucidated. In this study, we examined the clinical relevance of miR-99b expression in breast cancer. We analyzed miRNA and mRNA expression and their relationships with clinical parameters in 1,961 breast cancer samples from two independent large cohorts, the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas (TCGA). Several algorithms, including gene set enrichment analysis (GSEA) and xCell, have been used to investigate biological functions and the tumor microenvironment. High miR-99b expression significantly enriched the mTORC1 signaling gene set in breast cancer (NES = 1.63, FDR = 0.03, and NES = 1.58, FDR = 0.10, in METABRIC and TCGA, respectively). No other mechanisms, including the epithelial mesenchymal transition, NFκB, and TGF-ß signaling, were consistently enriched in both cohorts. MiR-99b-high breast cancer was associated with high homologous recombination deficiencies, intratumor heterogeneity, and high rates of mutation and neoantigens. In agreement, miR-99b-high breast cancer was associated with increased cell proliferation, correlating with Nottingham histological grade, and significant enrichment of E2F targets, G2/M checkpoint, and mitotic spindle gene sets consistently in both cohorts (P = 0.01, P < 0.001). High miR-99b levels were also associated with low stromal cell fractions in the tumor microenvironment, including adipocytes, keratinocytes, and lymphatic endothelial cells (P < 0.001). However, in both cohorts, miR-99b expression was not associated with significant infiltration of immune cells, except dendritic cells (P = 0.006, 0.020). Finally, in both cohorts, breast cancer with high miR-99b expression was significantly associated with worse disease-free survival (DSS) and overall survival (OS), particularly in estrogen receptor (ER)-positive/human epidermal growth factor (HER)2-negative breast cancer (DSS hazard ratio (HR) 1.29, 95% confidence interval (CI) 1.10-1.51, P < 0.001 in the METABRIC cohort and HR 1.82, 95% CI 1.12-2.98, P = 0.017 in the TCGA cohort). In conclusion, breast cancer with high miR-99b expression was significantly associated with mTORC1 signaling, cell proliferation, and decreased patient survival, particularly in the ER-positive/HER2-negative subtype.

Development of a novel BRCAness score that predicts response to PARP inhibitors.

BACKGROUND: BRCAness is a characteristic feature of homologous recombination deficiency (HRD) mimicking BRCA gene mutation in breast cancer. We hypothesized that a measure to quantify BRCAness that causes synthetic lethality in BRCA mutated tumors will identify responders to PARP inhibitors. METHODS: A total of 6753 breast cancer patients from 3 large independent cohorts were analyzed. A score was generated by transcriptomic profiling using gene set variation analysis algorithm on 34 BRCA1-mutation related genes selected by high AUC levels in ROC curve between BRCA1 mutation and wildtype breast cancer. RESULTS: The score was significantly associated with BRCA1 mutation, high mutation load and intratumoral heterogeneity as expected, as well as with high HRD, DNA repair and MKi67 expression regardless of BRCA mutations. High BRCAness tumors enriched not only DNA repair, but also all five Hallmark cell proliferation-related gene sets. High BRCAness tumors were significantly associated with higher cytolytic activity and with higher anti-cancerous immune cell infiltration. Not only did the breast cancer cell lines with BRCA-mutation show high score, but even the other cells in human breast cancer tumor microenvironment were contributing to the score. The BRCAness score was the highest in triple-negative breast cancer consistently in all 3 cohorts. BRCAness was associated with response to chemotherapy and correlated strongly with response to PARP inhibitor in both triple-negative and ER-positive/HER2-negative breast cancer. CONCLUSIONS: We established a novel BRCAness score using BRCA-mutation-related gene expressions and found that it associates with DNA repair and predicts response to PARP inhibitors regardless of BRCA mutation.

A case of matrix-producing carcinoma of the breast treated with preoperative chemotherapy.

Background: Matrix-producing carcinoma (MPC) is a rare tumor accounting for 0.1% of all breast cancers. Although MPC is usually triple-negative breast cancer, there have been few reports of preoperative chemotherapy for MPC that is considered chemotherapy-resistant. Herein, we report a case of MPC that was successfully treated with preoperative chemotherapy. Case Description: The patient was a 47-year-old woman diagnosed with right multiple breast cancer, clinical stage IIA. One of the tumors was identified as MPC and the other was invasive ductal carcinoma. The maximum tumor diameter of MPC was 3.8-cm. On immunohistochemistry, the tumor cells of MPC tested negative for estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2). The Ki67 index was 90%. Preoperative chemotherapy was performed. EC (epirubicin 90 mg/m2 and cyclophosphamide 600 mg/m2) was administered every 3 weeks for a total of 4 courses, followed by 12 courses of weekly paclitaxel (80 mg/m2). Then, she underwent right skin-sparing mastectomy, sentinel lymph node biopsy, and deep inferior epigastric perforator flap reconstruction. There was no metastasis to the sentinel lymph nodes. Postoperative pathological results showed that the residual tumor of the MPC measured only 0.1 cm. On the other hand, the residual tumor of the invasive ductal carcinoma was 0.7 cm. Endocrine therapy with oral tamoxifen was initiated for the invasive ductal carcinoma. Three years after surgery, no recurrence was observed. It has been reported that prognosis was correlated with residual cancer after preoperative chemotherapy. In addition, preoperative chemotherapy is of high clinical significance for the selection of postoperative treatment. Conclusions: Although our case of MPC was successfully treated with preoperative chemotherapy, the standard of care for MPC remains uncertain. Development of a new targeted therapy for MPC is warranted.

Stratification of Prognosis by Biological Features Following Neoadjuvant Chemotherapy in Luminal Breast Cancer.

BACKGROUND/AIM: There are few models predicting breast cancer prognosis among patients receiving neoadjuvant chemotherapy (NAC) for estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative (luminal) breast cancer. We examined whether biological features (BFs) of residual tumors are prognostic factors following NAC. PATIENTS AND METHODS: We enrolled patients with remnant tumors following NAC for luminal breast cancer and evaluated clinical stage, pathological stage, BFs prior to NAC, and BFs following NAC as prognostic factors. BFs were divided into high and low risk using the previously reported YR-IHC4 model calculated according to ER, progesterone receptor (PgR), HER2, and the proliferation marker Ki-67. RESULTS: A total of 57 patients were enrolled in the current study. We observed a statistically significant difference in relapse-free survival (RFS) between the BF risk categories via YR-IHC4 predictions following NAC (p=0.044). The 5-year RFS rates of the BF low- and high-risk groups following NAC were 84.2% and 52.5%, respectively. CONCLUSION: BFs of residual tumors following NAC may be important prognostic factors in luminal breast cancer.

Evaluation of aesthetic outcomes of breast-conserving surgery by the surgeon, nurse, and patients.

BACKGROUND: Evaluation of the cosmetic outcome after breast-conserving surgery (BCS) differs depending on the evaluator. We performed a clinical trial to examine the differences between assessments of cosmetic outcomes performed by a surgeon, patients, and a nurse as a third party after BCS; the evaluation was performed two times (at 3 months and 9 months after surgery). Similarly, we identified factors most significantly affecting the overall cosmetic outcomes. METHODS: Sixty-eight patients with primary breast cancer who had undergone BCS between September 2017 and December 2018 were consecutively enrolled in the study. Breast shape, symmetry, hardness, scarring, and overall outcomes were evaluated by a surgeon, patients, and a nurse via a questionnaire. RESULTS: Intraclass correlation coefficients (ICCs) for the 3- to 9-month comparisons of the surgeon, patients, and nurse were 0.73, 0.64, and 0.29, respectively. The ICCs for the surgeon-patient, nurse-patient, and surgeon-nurse comparisons (3 months/9 months) were 0.49/0.44, 0.34/0.10, and 0.41/0.51, respectively. The partial regression coefficient for shape was 0.45 (p = 0.003)/0.61 (p = 0.001), 0.37 (p = 0.005)/0.50 (p < 0.001), and -0.08 (p = 0.48)/0.58 (p < 0.001) for evaluations performed by the surgeon, patients, and nurse, 3 months and 9 months, respectively. CONCLUSION: With reproducibility, only moderate agreement was observed between the surgeon and the patients. Breast shape was identified as the most important factor affecting cosmetic outcomes.

Clinical Impact of a Novel Model Predictive of Oncotype DX Recurrence Score in Breast Cancer.

BACKGROUND/AIM: Oncotype DX recurrence score (RS) for breast cancer is a useful tool for determining chemotherapy indication but it is expensive and time-consuming. We determined whether four immuno-histochemical markers, namely human epidermal growth factor 2 (HER2), estrogen receptor (ER), progesterone receptor (PgR), and Ki-67, are predictive of an RS ≥26 in Japanese patients. PATIENTS AND METHODS: The study included 95 Japanese patients evaluated for RS. A predictive model was created using logistic regression analysis. RESULTS: The discriminant function was calculated as follows: p=1/{1+exp [-(4.611+1.2342×HER2-0.0813×ER- 0.0489 ×PgR+0.0857×Ki67)]}. Using a probability of 0.5 as the cutoff, the accuracy, sensitivity, specificity, positive predictive and negative predictive values were 90.5%, 72.2%, 94.8%, 76.4% and 93.5%, respectively. CONCLUSION: The model had a high negative predictive value in predicting RS ≥26 in Japanese patients, indicating that Oncotype DX testing may be omitted in patients with a negative result according to the predictive model.

Predicting Nonsentinel Lymph Node Metastasis in Breast Cancer: A Multicenter Retrospective Study.

BACKGROUND: Sentinel lymph node (SLN) biopsy has been the standard modality for breast cancer patients with clinically node negative disease. In patients who undergo axillary lymph node dissection (ALND) due to SLN metastasis, the harvested nodes (non-SLNs) often contain no metastasis. Here, we evaluated the predictive factors associated with non-SLN metastasis in breast cancer patients. MATERIALS AND METHODS: This was a retrospective study of patients with operable cT1-3, cN0 invasive breast cancer who underwent SLN biopsy followed by ALND due to SLN metastasis. The clinicopathologic factors and predictive factors of non-SLN metastasis were analyzed. The optimal cutoff for the Ki67 index and the number of positive and negative SLNs that were predictive of non-SLN metastasis were evaluated using receiver operating characteristic curves. RESULTS: The median number of SLN and non-SLN was 3 and 11, respectively. Of the 150 patients, 52 (35.0%) had metastases in non-SLNs. The optimal cutoffs for the Ki67 index and the number of positive and negative SLNs were of 12%, 2, and 1, respectively. In the univariate analysis, the Ki67 index and the number of positive SLNs≥2 and negative SLNs≤1 were higher in the non-SLN + group than that in the non-SLN - group. The number of negative SLNs was as a predictive factor for non-SLNs metastasis in the multivariate analysis. CONCLUSIONS: The number of negative SLNs predicts the risk of non-SLN metastasis in breast cancer. When deciding on whether to omit ALND, the number of positive and negative SLNs should be considered.

First-line Gemcitabine Versus Treatment of Physician's Choice for Metastatic Breast Cancer: A Prospective Cohort Study.

BACKGROUND/AIM: This study aimed to investigate the efficacy of first-line gemcitabine monotherapy for metastatic breast cancer (MBC) and its effect on health-related quality of life (HRQoL) compared with treatment of physician's choice (TPC). PATIENTS AND METHODS: We enrolled 96 patients into the first-line gemcitabine group (n=47) or other treatment of physician's choice (TPC) group (n=49) from May 2010 to April 2013. HRQoL was evaluated every 4 weeks. RESULTS: There was no significant difference in the median time to treatment failure (5.3 vs. 4.6 months, hazard ratio=0.87, p=0.546) and the incidence rates of grade 3/4 haematological toxicity (10.6% vs. 8.1%, p=0.677) and grade 3/4 non-haematological toxicity (4.2% vs. 8.1%, p=0.429) between the gemcitabine and TPC groups. Changes in HRQoL from baseline to 12 weeks were not significantly different. CONCLUSION: Gemcitabine achieves similar efficacy and HRQoL benefit to other chemotherapy and can be used as first-line treatment for MBC.

Breast cancer suspected to originate from familial hereditary tumors: A case report.

If familial hereditary tumor is suspected, diagnosis and treatment should always be performed considering the presence of familial hereditary tumors irrespective of whether genetic testing is performed.

Clinical and pathological predictors of recurrence in breast cancer patients achieving pathological complete response to neoadjuvant chemotherapy.

INTRODUCTION: Despite the excellent prognosis associated with pathological complete response (pCR) to neoadjuvant chemotherapy (NAC), some patients still develop recurrence. Here, we investigated the outcomes of breast cancer patients with pCR, as well as the clinical and pathological predictors of cancer recurrence in these patients. MATERIALS AND METHODS: Of the 1599 breast cancer patients treated with NAC, we evaluated 394 patients who achieved pCR between January 2007 and December 2016. pCR was defined as no evidence of invasive cancer in breast. Residual in situ ductal and axillary lymph node diseases were not considered. We analyzed the outcomes using the Kaplan-Meier method. We assessed the association of clinical and pathological predictors with cancer recurrence using the cox proportional hazards regression model. RESULTS: The median follow-up time was 63 months. The 5-year disease-free survival rate was 92.3%. Cancer recurrence was observed in 28 patients (7.1%): local recurrence 8 patients (2.0%), visceral metastasis 10 patients (2.5%), and brain metastasis 10 patients (2.5%). Brain metastases were found in patients with HER2 type breast cancer. The significant predictors of cancer recurrence were HER2 positivity (p = 0.04), clinical tumor size (p < 0.01), and lymph node metastasis (p < 0.01) before NAC on univariate analysis and only lymph node metastasis on multivariate analysis. CONCLUSION: Patients achieving pCR to NAC showed excellent outcomes. Advanced clinical stage, large tumor size, presence of lymph node metastasis, and HER2 positivity before NAC were identified as significant predictors of cancer recurrence. Residual in situ ductal and lymph node diseases after NAC were not significant predictors.

Matrix-producing Carcinoma as an Aggressive Triple-negative Breast Cancer: Clinicopathological Features and Response to Neoadjuvant Chemotherapy.

BACKGROUND: Breast matrix-producing carcinomas (MPCs) are rare, and usually triple-negative (TNBC; i.e. oestrogen receptor-, progesterone receptor-, and human epidermal growth factor receptor 2-negative). This study evaluated the clinical features, immunohistochemical profiles, and pathological response to neoadjuvant chemotherapy (NAC) of patients with MPCs. PATIENTS AND METHODS: Five MPCs were identified among 247 patients with TNBC receiving anthracycline- and taxane-based NAC. Pathological response was assessed using surgical specimens. RESULTS: All tumours were histological grade 3 according to pre-treatment core biopsies. Mean Ki-67 and p53 positivity were 65% and 90%, respectively. All tumours were TNBC, and epidermal growth factor receptor-, cytokeratin 5/6-, and vimentin-positive. Grade 3 (pathological complete response) was achieved in 0% (0/5) and 32% (77/242) of those with MPCs and with TNBCs of no specific histological type, respectively, and grade 1a (poor response) in 80% (4/5) and 13% (31/242), respectively. CONCLUSION: MPCs are basal-type TNBCs expressing epithelial-mesenchymal transition markers, with a poor response to standard NAC. Further studies are needed to improve the treatment of this rare but aggressive tumour.

Anthracycline could be essential for triple-negative breast cancer: A randomised phase II study by the Kanagawa Breast Oncology Group (KBOG) 1101.

BACKGROUND: It is important to determine whether anthracycline-containing regimens or taxane-containing regimens are more effective in individual patients. The present study compared the efficacy of six cycles of docetaxel and cyclophosphamide (TC6) with that of three cycles of 5-fluorouracil, epirubicin and cyclophosphamide followed by docetaxel (FEC-D) in Japanese patients with hormone receptor (HR)-negative breast cancer (BC) to identify subtypes requiring anthracycline treatment. METHODS: The study included 103 patients with operable HR-negative BC. Of these patients 53 received FEC-D and 50 received TC6. The primary endpoint was pathological complete response (pCR). The secondary endpoints were safety, breast-conserving surgery, disease-free survival (DFS) and overall survival (OS). The predictive factors for each regimen were evaluated. RESULTS: Of the 103 patients, 97 completed the study (FEC-D, 50 patients; TC6, 47 patients). The pCR rate was higher with FEC-D (36%) than with TC6 (25.5%); however, the difference was not significant (P = 0.265). TC6 was safer than FEC-D, as the adverse events with docetaxel in the FEC-D regimen were similar to those with the TC6 regimen. Among patients with basal BC, the pCR rate was significantly higher with FEC-D (42.9%) than with TC6 (13.6%; P = 0.033). Among patients with triple-negative breast cancer (TNBC), the DFS and OS were significantly better with FEC-D than with TC6 (P = 0.016 and P = 0.034, respectively). CONCLUSION: TC6 was not as effective as FEC-D for treating HR-negative BC, as TC6 was not sufficient to treat TNBC, particularly the basal subtype. Our findings suggest that anthracyclines are better treatment options than taxanes for basal BC.

Participants in a randomized controlled trial had longer overall survival than non-participants: a prospective cohort study.

PURPOSE: While some studies show improved outcomes in clinical trial participants as compared to non-participants, existence of such a trial effect has not been proved precisely. METHODS: This was a prospective cohort study to compare the prognoses for participants in the randomized controlled trial (SELECT BC) and non-participants. SELECT BC compared S-1 and taxane as first-line treatment for metastatic breast cancer. Non-participants were all patients who met the eligibility criteria of SELECT BC and who had been requested to participate in that trial by attending doctors and declined. The study aimed to compare the prognoses between participants and non-participants. The primary endpoint was median overall survival. RESULTS: The median OS in participants was significantly superior to that in non-participants with a statistically significant difference (36.8 months vs. 25.2 months. HR 1.48, p = 0.022). A similar result was obtained when only patients who received the same chemotherapy (S-1 or taxane) used in SELECT BC after declining participation were assumed as non-participants (36.8 months vs. 22.0 months. HR 2.03, p = 0.006). CONCLUSIONS: This study may suggest the existence of a trial effect, in which, for a given treatment, participation in a clinical trial is associated with a better outcome.

Tumor-targeting Salmonella typhimurium A1-R overcomes partial carboplatinum-resistance of a cancer of unknown primary (CUP).

Cancer of unknown primary (CUP) is metastatic disease without a known primary and therefore very difficult to identify effective therapy. Previously, we demonstrated partial efficacy of Salmonella typhimurium A1-R (S. typhimurium A1-R) alone and carboplatinum alone (CAR) on a CUP patient tumor in the patient-derived xenograft (PDOX) model. The aim of the present study was to investigate the efficacy of S. typhimurium A1-R combined with CAR on the CUP PDOX model. The CUP tumors were implanted orthotopically into the left supraclavicular fossa of nude mice to match the site from which they were resected from the patient. CUP PDOX models were divided randomly into the following 4 groups after the tumor volume reached 100 mm3: G1: untreated group; G2: CAR (30 mg/kg, i.p., weekly, 2 weeks); G3: S. typhimurium A1-R (5x107 CFU/body, i.v., weekly, 2 weeks).; G4: S. typhimurium A1-R combined with CAR (S. typhimurium A1-R; 5x107 CFU/body, i.v., weekly, 2 weeks; CAR, 30 mg/kg, i.p., weekly, 2 weeks). Each group comprised 7 mice. All mice were sacrificed on day 15. Tumor volume and body weight were measured twice a week. S. typhimurium A1-R and CAR moderately inhibited tumor growth compared to the untreated group on day 15 (P < 0.001 and P < 0.001, respectively). S. typhimurium A1-R combined with CAR inhibited the tumor growth significantly more compared to S. typhimurium A1-R monotherapy or CAR monotherapy on day 15 (P = 0.004 and P = 0.001, respectively). The present report demonstrates that S. typhimurium A1-R can increase the efficacy of a standard drug used for CUP in a PDOX model.

Tumor-targeting Salmonella typhimurium A1-R suppressed an imatinib-resistant gastrointestinal stromal tumor with c-kit exon 11 and 17 mutations.

Gastrointestinal stromal tumor (GIST) is a refractory disease in need of novel efficacious therapy. The aim of our study was to evaluate the effectiveness of tumor-targeting Salmonella typhimurium A1-R (S. typhimurium A1-R) using on a patient derived orthotopic xenograft (PDOX) model of imatinib-resistant GIST. The GIST was obtained from a patient with regional recurrence, and implanted in the anterior gastric wall of nude mice. The GIST PDOX mice were randomized into 3 groups of 6 mice each when the tumor volume reached 60 mm3: G1, control group; G2, imatinib group (oral administration [p.o.], daily, for 3 weeks); G3, S. typhimurium A1-R group (intravenous [i.v.] injection, weekly, for 3 weeks). All mice from each group were sacrificed on day 22. Relative tumor volume was estimated by laparotomy on day 0 and day 22. Body weight of the mouse was evaluated 2 times per week. We found that S. typhimurium A1-R significantly reduced tumor growth in contrast to the untreated group (P = 0.001). In addition, we found that S. typhimurium A1-R was more effective compared to imatinib (P = 0.013). Furthermore, Imatinib was not significantly effective compared to the control group (P = 0.462). These results indicate that S. typhimurium A1-R may be new effective therapy for imatinib-resistant GIST and therefore a good candidate for clinical development of this disease.

Patient-derived orthotopic xenograft models for cancer of unknown primary precisely distinguish chemotherapy, and tumor-targeting S. typhimurium A1-R is superior to first-line chemotherapy.

Cancer of unknown primary (CUP) is a recalcitrant disease with poor prognosis because it lacks standard first-line therapy. CUP consists of diverse malignancy groups, making personalized precision therapy essential. The present study aimed to identify an effective therapy for a CUP patient using a patient-derived orthotopic xenograft (PDOX) model. This paper reports the usefulness of the PDOX model to precisely identify effective and ineffective chemotherapy and to compare the efficacy of S. typhimurium A1-R with first-line chemotherapy using the CUP PDOX model. The present study is the first to use a CUP PDOX model, which was able to precisely distinguish the chemotherapeutic course. We found that a carboplatinum (CAR)-based regimen was effective for this CUP patient. We also demonstrated that S. typhimurium A1-R was more effective against the CUP tumor than first-line chemotherapy. Our results indicate that S. typhimurium A1-R has clinical potential for CUP, a resistant disease that requires effective therapy.

Imaging the Governing Step of Metastasis in Gelfoam® Histoculture.

Distant organ colonization by cancer cells is the governing step of metastasis. We review in this chapter the modeling and imaging of organ colonization by cancer cells in Gelfoam® histoculture. ANIP 973 lung cancer cells expressing green fluorescent protein (GFP) were injected intravenously into nude mice, whereby they formed brilliantly fluorescing metastatic colonies on the mouse lung. The seeded lung tissue was then excised and incubated in the three-dimensional Gelfoam® histoculture that maintained the critical features of progressive in vivo organ colonization. Tumor progression was continuously visualized by GFP fluorescence of individual cultures over a 52-day period, during which tumor colonies spread throughout the lung. Organ colonization was selective in Gelfoam® histoculture for lung cancer cells to grow on lung tissue, since no growth occurred on histocultured mouse liver tissue. The ability to support selective organ colonization in Gelfoam® histoculture and visualize tumor progression by GFP fluorescence allows the in vitro study of the governing processes of metastasis.