Stroma-poor Tumors Research Articles

Unselective Measurement of Tumor-to-Stroma Proportion in Colon Cancer at the Invasion Front-An Elusive Prognostic Factor: Original Patient Data and Review of the Literature.

The tumor-to-stroma ratio is a highly debated prognostic factor in the management of several solid tumors and there is no universal agreement on its practicality. In our study, we proposed confirming or dismissing the hypothesis that a simple measurement of stroma quantity is an easy-to-use and strong prognostic tool. We have included 74 consecutive patients with colorectal cancer who underwent primary curative abdominal surgery. The tumors have been grouped into stroma-poor (stroma < 10%), medium-stroma (between 10 and 50%) and stroma-rich (over 50%). The proportion of tumor stroma ranged from 5% to 70% with a median of 25%. Very few, only 6.8% of patients, had stroma-rich tumors, 4% had stroma-poor tumors and 89.2% had tumors with a medium quantity of stroma. The proportion of stroma, at any cut-off, had no statistically significant influence on the disease-specific survival. This can be explained by the low proportion of stroma-rich tumors in our patient group and the inverse correlation between stroma proportion and tumor grade. The real-life proportion of stroma-rich tumors and the complex nature of the stroma-tumor interaction has to be further elucidated.

Influence of Tumor Stroma on the Aggressiveness of Poorly Cohesive Gastric Carcinoma.

Tumor-stroma crosstalk promotes the adaptation of cancer cells to the local microenvironment and sustains their growth. We assessed the quantitative and qualitative impact of intralesional stroma on clinic-pathological features and the prognosis of poorly cohesive gastric cancer (PCGC) variants. Tissue microarrays including 75 PCGC specimens were immunostained for cytokeratin 8/18 and α-smooth muscle actin to assess the relative proportion of neoplastic cells versus stromal components and the cases were subsequently divided into stroma-rich (SR) and stroma-poor (SP) tumors. Stromal status is significantly associated with the depth of tumor invasion. Patient survival rate was found to be higher in the SP compared to the SR tumor group and, hence, abundant stroma was identified as a significant risk factor in univariable analysis but had no independent prognostic impact. We also investigated the mRNA levels of KRT8 and the associated transcriptional signatures using the molecular data of 82 PCGC cases divided into KRT8-high and KRT8-low groups. KRT8-high tumors were enriched in proteins localized in the extracellular compartment and their expression levels correlated with longer survival in the KRT8-high group and shorter overall survival in the KRT8-low group. Comprehensively, we find that relative intralesional stromal content is a marker of aggressiveness in PCGC tumors and that extracellular proteins characterize functionally and clinically different PCGC subgroups.

Tumor-stroma ratio can predict lymph-node metastasis in cT1/2N0 oral tongue squamous cell carcinoma independent of tumor budding grade.

cT1/2 oral tongue squamous cell carcinoma (OTSCC) often metastasizes to cervical lymph nodes. However, predicting neck lymph-node metastasis (NLM) remains challenging. Pathomorphological evaluation of tumor budding grade (TBG) and tumor-stroma ratio (TSR) reportedly can predict lymph-node metastases. Hence, this study aimed to evaluate TBG and TSR in OTSCC and investigate their relationship to occult NLM and cancer relapse. Clinicopathological data of patients with cT1/2N0 OTSCC treated at the University of Tokyo Hospital between 2007 and 2017 were collected. TBG and TSR were evaluated using hematoxylin-eosin staining and cytokeratin AE1/AE3 immunostaining. Out of 70 patients, 16 underwent elective neck dissection in addition to primary-tumor resection, whereas 54 did not. During follow-up, NLM was found in 35 patients. NLM correlated with the pathological depth of invasion (pDOI) (p < 0.001), TBG (p = 0.008), and TSR (p < 0.001) in univariate analysis and pDOI (p = 0.01) and TSR (p = 0.02) in multivariate analysis. The 5-year recurrence-free survival rate (RFS) was 78% for patients with a pDOI ≤ 5mm and stroma-poor tumors and 33% for patients with a pDOI > 5mm and stroma-rich tumors. Patients with a pDOI > 5mm and stroma-rich tumors have a high risk for cancer relapse. TSR and pDOI may be promising NLM predictors in cT1/2N0 OTSCC.

Differences in stromal component of chordoma are associated with contrast enhancement in MRI and differential gene expression in RNA sequencing

Chordoma is a malignant bone neoplasm demonstrating notochordal differentiation and it frequently involves axial skeleton. Most of chordomas are conventional type with varying amount of myxoid stroma. Previously known prognostic factors for conventional chordoma are not specific for chordoma: old age, metastasis, tumor extent, and respectability. Here, we aimed to investigate the histologic, radiologic, and transcriptomic differences in conventional chordoma based on the stromal component. A total of 45 patients diagnosed with conventional chordoma were selected between May 2011 and March 2020 from a single institution. Electronic medical records, pathology slides, and pretreatment magnetic resonance imaging (MRI) scans were reviewed. Of the 45 patients, ten cases (4 stroma-rich and 6 stroma-poor tumor) were selected for RNA sequencing, and available cases in the remainder were used for measuring target gene mRNA expression with qPCR for validation. Differential gene expression and gene set analysis were performed. Based on histologic evaluation, there were 25 (55.6%) stroma-rich and 20 (44.4%) stroma-poor cases. No clinical differences were found between the two groups. Radiologically, stroma-rich chordomas showed significant signal enhancement on MRI (72.4% vs 27.6%, p = 0.002). Upregulated genes in stroma-rich chordomas were cartilage-, collagen/extracellular matrix-, and tumor metastasis/progression-associated genes. Contrarily, tumor suppressor genes were downregulated in stroma-rich chordomas. On survival analysis, Kaplan–Meier plot was separated that showed inferior outcome of stroma-rich group, although statistically insignificant. In conclusion, the abundant stromal component of conventional chordoma enhanced well on MRI and possibly contributed to the biological aggressiveness that supported by transcriptomic characteristics. Further extensive investigation regarding radiologic-pathologic-transcriptomic correlation in conventional chordoma in a larger cohort could verify additional clinical significance.

Predictive Role of Tumor-Stroma Ratio for Survival of Patients With Non-Small Cell Lung Cancer: A Meta-Analysis.

Background: Role of tumor-stroma ratio (TSR) as a predictor of survival in patients with non-small cell lung cancer (NSCLC) remains not clear. A systematic review and meta-analysis was conducted to summarize current evidence for the role of TSR in NSCLC. Methods: Relevant cohort studies were retrieved via search of Medline, Embase, and Web of Science databases. The data was combined with a random-effect model by incorporating the between-study heterogeneity. Specifically, subgroup and meta-regression analyses were performed to explore the association between TSR and survival in patients with squamous cell carcinoma (SCC) or adenocarcinoma (AC). Results: Nine cohort studies with 2031 patients with NSCLC were eligible for the meta-analysis. Pooled results showed that compared to those stroma-poor tumor, patients with stroma rich NSCLC were associated with worse recurrence-free survival (RFS, hazard ratio [HR] = 1.52, 95% confidence interval [CI]: 1.07 to 2.16, p = 0.02) and overall survival (OS, HR = 1.48, 95% CI: 1.20 to 1.82, p < 0.001). Subgroup analyses showed that stroma-rich tumor may be associated with a worse survival of SCC (HR = 1.89 and 1.47 for PFS and OS), but a possibly favorable survival of AC (HR = 0.28 and 0.69 for PFS and OS). Results of meta-regression analysis also showed that higher proportion of patients with SCC was correlated with higher HRs for RFS (Coefficient = 0.012, p = 0.03) and OS (Coefficient = 0.014, p = 0.02) in the included patients, while higher proportion of patients with AC was correlated with lower HRs for RFS (Coefficient = −0.012, p = 0.03) and OS (Coefficient = −0.013, p = 0.04), respectively. Conclusion: Tumor TSR could be used as a predictor of survival in patients with NSCLC. The relative proportion of patients with SCC/AC in the included NSCLC patients may be an important determinant for the association between TSR and survival in NSCLC. Stroma richness may be a predictor of poor survival in patients with lung SCC, but a predictor of better survival in patients with lung AC.

Stromal scoring in advanced colon and rectal cancer: Stroma-rich tumors and their association with aggressive phenotypes

Background: Our aim was to explore relevance of the proportion between neoplastic cell component and tumor-associated stroma in order to assess its association with confirmed aggressive phenotypes of right/left colon and rectum cancers in a large series of patients. Methods: The quantification of stroma component was performed in patients diagnosed with colorectal adenocarcinoma who underwent surgical resection. The analyzed variables were age, gender, anatomical/pathological features, and tumor-stroma proportion. Tumor-stroma proportion was estimated based on slides used in routine pathology for determination of T status and was described as low, with a stromal percentage ?50% or high, with a stromal percentage &gt;50%. The tumor-stroma proportion was estimated by two observers, and the inter-observer agreement was assessed. Results: The sample included 390 colorectal adenocarcinoma patients. Stroma-rich tumors were observed in 53.3% of cases. Well-differentiated tumors had the lowest stromal proportions (p = 0.028). Stroma-poor tumors showed less depth of invasion (p&lt;0.001). High stromal content was observed in association with tumor budding, perineural, angiolymphatic, and lymph node involvement, and distant metastasis (p?0.001). Colorectal adenocarcinoma without lymph node or distant metastasis involvement had lower stromal proportion, while metastatic ones exhibited high stromal content (p &lt;0.001). The inter-rater reliability (concordance) between the estimations of pathologists for tumor-stroma proportions was high (?=0.746). Conclusion: The tumorstroma proportion in colorectal adenocarcinoma was associated with adverse prognostic factors, reflecting the stage of the disease. Stroma-rich tumors showed a significant correlation with advancement of the disease and its aggressiveness. Due to its availability tumor-stroma proportion evaluation has high application potential and can complement current staging system for colorectal adenocarcinoma.

Isoform specific anti-TGF\u03b2 therapy enhances antitumor efficacy in mouse models of cancer

TGFβ is a potential target in cancer treatment due to its dual role in tumorigenesis and homeostasis. However, the expression of TGFβ and its inhibition within the tumor microenvironment has mainly been investigated in stroma-heavy tumors. Using B16 mouse melanoma and CT26 colon carcinoma as models of stroma-poor tumors, we demonstrate that myeloid/dendritic cells are the main sources of TGFβ1 and TGFβ3. Depending on local expression of TGFβ isoforms, isoform specific inhibition of either TGFβ1 or TGFβ3 may be effective. The TGFβ signature of CT26 colon carcinoma is defined by TGFβ1 and TGFβ1 inhibition results in tumor delay; B16 melanoma has equal expression of both isoforms and inhibition of either TGFβ1 or TGFβ3 controls tumor growth. Using T cell functional assays, we show that the mechanism of tumor delay is through and dependent on enhanced CD8+ T cell function. To overcome the local immunosuppressive environment, we found that combining TGFβ inhibition with immune checkpoint blockade results in improved tumor control. Our data suggest that TGFβ inhibition in stroma poor tumors shifts the local immune environment to favor tumor suppression.

Diffusion Kurtosis Imaging-A Superior Approach to Assess Tumor-Stroma Ratio in Pancreatic Ductal Adenocarcinoma.

Extensive desmoplastic stroma is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and contributes to tumor progression and to the relative resistance of tumor cells towards (radio) chemotherapy. Thus, therapies that target the stroma are under intense investigation. To allow the stratification of patients who would profit from such therapies, non-invasive methods assessing the stroma content in relation to tumor mass are required. In the current prospective study, we investigated the usefulness of diffusion-weighted magnetic resonance imaging (DW-MRI), a radiologic method that measures the random motion of water molecules in tissue, in the assessment of PDAC lesions, and more specifically in the desmoplastic tumor stroma. We made use of a sophisticated DW-MRI approach, the so-called diffusion kurtosis imaging (DKI), which possesses potential advantages over conventional and widely used monoexponential diffusion-weighted imaging analysis (cDWI). We found that the diffusion constant D from DKI is highly negatively correlated with the percentage of tumor stroma, the latter determined by histology. D performed significantly better than the widely used apparent diffusion coefficient (ADC) from cDWI in distinguishing stroma-rich (>50% stroma percentage) from stroma-poor tumors (≤50% stroma percentage). Moreover, we could prove the potential of the diffusion constant D as a clinically useful imaging parameter for the differentiation of PDAC-lesions from non-neoplastic pancreatic parenchyma. Therefore, the diffusion constant D from DKI could represent a valuable non-invasive imaging biomarker for assessment of stroma content in PDAC, which is applicable for the clinical diagnostic of PDAC.

Intravoxel incoherent motion diffusion-weighted MRI in patients with breast cancer: Correlation with tumor stroma characteristics

PurposeTo determine whether imaging parameters derived from intravoxel incoherent motion (IVIM) diffusion weighted imaging (DWI) vary according to tumor-stroma ratio(TSR) or dominant stroma type of breast cancer. MethodsWe prospectively enrolled 77 patients with breast cancer who underwent IVIM DWI on a 3.0 T MR scanner. The values of IVIM parameters (D, D* and f) were measured. After surgery, TSR or dominant stroma type was evaluated. The relationship between imaging parameters and tumor stroma characteristics was analyzed. ResultsThe mean D and f values were lower in stroma-poor tumor than in stroma-rich tumor (P = 0.012, 0.015). The mean D value was lower in the collagen-dominant type than in fibroblast-dominant or lymphocyte-dominant type (P = 0.032, 0.043). According to multivariate linear regression analyses, tumor size (P = 0.007), TSR (P = 0.008), dominant stroma type (collagen dominant, P = 0.012), and histological grade (P = 0.031) were independently correlated with D value; and tumor size (P = 0.011), TSR (P = 0.021) and histological grade (P = 0.037) were independently correlated with f value. ConclusionIn breast cancer, D and f values show significant differences according to TSR, and D value is lower in collagen dominant type than in fibroblast dominant or lymphocyte dominant types.

Isoform specific anti-TGFβ therapy enhances antitumor efficacy in mouse models of cancer

Abstract TGFβ is a pleotropic cytokine, which has emerged as a potential target in cancer treatment due to its dual role in tumorigenesis and homeostasis. There are three isoforms of TGFβ (TGFβ1, TGFβ2 and TGFβ3), which are secreted by immune and nonimmune cells as an inactive latent complex. Depending on the local context and players, TGFβ can adopt opposing roles in carcinogensis and in modulating the immune system. However, the expression of TGFβ isoforms within the tumor microenvironment and isoform specific inhibition remains to be investigated. The main source of TGFβ isoforms in the tumor microenvironment of B16 melanoma are infiltrating immune cells, with TGFβ1 and TGFβ3 being highly expressed on myeloid and dendritic cells. The CD45− population from B16 tumors demonstrated a lower expression of both TGFβ isoforms. Compared to untreated control animals, anti-TGFβ3 therapy resulted in the greatest delay in B16 tumor growth, followed by anti-TGFβ1 therapy and pan-TGFβ blockade. However, none of the therapies resulted in improved overall survival. Similar results were achieved in a 4T1 breast model. T cell functional assays demonstrated that anti-TGFβ3 resulted in CD8+ T cells with greater cytolytic ability as they showed higher granzyme B expression and killing against B16 cells when plated ex-vivo. Anti-TGFβ1 treatment resulted in greater interferon-γ production by CD8+ T cells, suggesting an increase in antigen-specificity. Isoform specific TGFβ inhibition in combination with immune checkpoint blockade demonstrated improved tumor control and survival. This provides rationale for the use of anti-TGFβ therapy in stroma poor tumors, such as melanoma, and for its potential to enhance the effectiveness of existing therapies.

Prognostic significance of tumor budding, tumor-stroma ratio, cell nests size, and stroma type in laryngeal and pharyngeal squamous cell carcinomas.

Despite immune microenvironment of head and neck squamous cell carcinoma (HNSCC) has been studied, there are no sufficient data on the role of tumor stroma factors. The aim of the study was to explore the prognostic and predictive role of these factors in a large series of HNSCC. This is a retrospective study of 266 patients with laryngeal and pharyngeal SCC. Clinical data were correlated with the following histological parameters: tumor-stroma ratio (TSR), tumor budding activity (BA), cell nests size (CNS), and stroma type. Stroma-rich tumors, tumor budding, smaller CNS at core and front area, and fibroblastic stroma type, were all adverse prognostic factors (P < 0.0001, 0.001, 0.003, 0.001, 0.007, respectively). Stroma-poor tumors and with larger CNS showed good response to induction chemotherapy (P = 0.009 and 0.02, respectively). TSR, tumor budding, CNS, and stroma type are important prognostic and predictive factors in laryngeal and pharyngeal SCC.

Tumor-stroma ratio (TSR) in non-small cell lung cancer (NSCLC) patients after lung resection is a prognostic factor for survival.

In recent years, the tumor-stroma ratio (TSR) has been considered to a new and independent predictive variable for the prognosis of some kinds of neoplasms. The objective of this study was to assess the prognostic significance of the TSR in non-small cell lung cancer (NSCLC). A cohort of 261 NSCLC patients who underwent radical surgery of lung cancer were included in the present study. Two independent observers visually estimated the TSR on hematoxylin-eosin (H&E) stained tissue pathological slices. According to the proportion of stroma ≥50% or <50%, We separate the patients into two groups: those with stroma-poor and those with stroma-rich tumors. Both univariate and multivariate analyses disclosed that the TSR was associated with overall survival (OS) [hazard ratio (HR), 1.741; 95% confidence intervals (CI), 1.040-2.913 and HR, 1.904; 95% CI, 1.132-3.202, respectively]. The HR values for disease-free survival (DFS) were 1.795 (95% CI, 1.073-3.005) and 2.034 (95% CI, 1.210-3.420). The OS and DFS of patients with stroma-poor tumors were better than those with stroma-rich tumors. These results demonstrated that the TSR is a new prognostic factor for NSCLC. Stroma-poor tumors were associated with longer disease-free period and better prognosis than were stroma-rich tumors in NSCLC patients. The TSR may contribute to the development of individualized treatment for NSCLC in the future.

Prognostic significance of the tumor-stroma ratio in gallbladder cancer.

In recent years, the tumor-stroma ratio (TSR) has attracted increasing attention as an independent prognostic factor for several solid tumors. However, the importance of the stromal compartment has not been investigated yet in gallbladder cancer (GBC). The objective of this study is to investigate the prognostic value of TSR in GBC and the relationship between TSR and other known prognostic parameters. A total of 51 patients who underwent operations for gallbladder carcinoma were selected for this study. TSR was determined on haematoxylin and eosin (H et E)-stained sections by two independent investigators. Stromal ratio groups were classified as stroma-poor (ratio of stroma 50%). The Mann-Whitney test, the Chi-squared test, the Kaplan-Meier method, and the Cox proportional hazards model were used to analyze the data. The median survival time for patients in the stroma-rich group was 6.00 months (95% CI, 4.47-7.54). In contrast, for the stroma-poor group, the median survival time was 17.00 months (95% CI, 3.64-30.36). The 3-year overall survival rate was 19.7% in the stroma-poor group and 7.2% in the stroma-rich group. Patients with stroma-rich tumors had a worse prognosis than those with stroma-poor tumors (log-rank P = 0.004). According to the univariate analysis, the TSR, differentiation grade, pTNM stage, and operative methods were shown to be related to overall survival (OS) with statistical significance. The hazard ratio (HR) of TSR was 2.428 (95% CI, 1.29-4.58; P = 0.006). However, the TSR did not prove to be an independent prognostic factor in the multivariate analysis. Our study demonstrated that the tumor-stroma ratio (TSR) is an important prognostic parameter for gallbladder cancer (GBC). Stroma-rich tumors were associated with poor overall survival.

Tumor–stroma ratio is a prognostic factor for survival in hepatocellular carcinoma patients after liver resection or transplantation

The stromal compartment in several organs seems to play an important role in the initiation, growth, and progression of certain neoplasms. The tumor-stroma ratio (TSR) has been found to be an independent factor for prognosis of several types of carcinomas, but the effect of the TSR on hepatocellular carcinoma (HCC) has not been explored yet. The objective of the study is to evaluate the prognostic importance of TSR in HCC patients after liver resection or transplantation. A total of 300 patients with HCC who underwent liver resection or transplantation were included in this study. TSR was assessed on hematoxylin and eosin-stained sections by 2 independent investigators. Patients were divided into 2 groups: a stroma-rich group (stroma ≥ 50%) and a stroma-poor group (stroma < 50%). Chi-square test, Kaplan-Meier method, and Cox univariable and multivariable regression were used in to analyze the data. Among the post liver resection patients, the TSR was associated with overall survival (OS) in univariate and multivariate analyses (hazard ratio [HR], 4.35 [95% CI, 2.54-7.47] and HR, 2.55 [95% CI, 1.44-4.52], respectively). Among the post liver transplant patients, the TSR was also associated with OS in univariate and multivariate analyses (HR, 2.92 [95% CI, 1.63-5.23] and HR, 2.76 [95% CI, 1.47-4.85], respectively), and TSR with recurrence-free survival (RFS) in univariate and multivariate analyses (HR, 2.63 [95% CI, 1.42-4.86] and HR, 1.93 [95% CI, 1.03-3.62], respectively). Patients with stroma-poor tumor and who were within the Milan criteria or the UCSF criteria had a better in OS and RFS. We show for the first time that TSR is an independent prognostic factor for HCC patients after liver resection or transplantation. TSR may enable better identification of patients at risk for recurrence in HCC patients after curative treatment and may aid in patient management and development of individualized medicine for treatment of HCC.

Prognostic Significance of the Tumor-Stroma Ratio in Epithelial Ovarian Cancer.

Tumor-stroma ratio (TSR) has recently been identified as a promising prognostic parameter for several solid tumors. This study aimed to evaluate the prognostic role of TSR in epithelial ovarian cancer (EOC) and 838 EOC patients were enrolled in this study. TSR was estimated on hematoxylin-and-eosin-stained tissue sections from the most invasive part of the primary tumor. Patients were classified as stroma-rich or stroma-poor according to the proportion of stroma ≥50% or <50%. Chi-square test analysis revealed that TSR were significantly associated with FIGO stage, LN status, and recurrence or not (all of them P < 0.001). The higher stroma-rich proportions were found in EOC patients with advanced stage (36.13% versus 19.75%), LN metastasis (51.93% versus 27.25%), and recurrence (34.27% versus 6.82%). Stroma-rich EOC patients had obvious shorter median time of progression-free survival (29 versus 39 months) and overall survival (50 versus 58 months), respectively. TSR was an independent prognostic factor for the evaluation of PFS in EOC. Stroma-rich tumors had worse prognosis and higher risk of relapse compared with those in stroma-poor tumors in EOC patients. Considered easy to determine for routine pathological examination, TSR may serve as a new prognostic histological parameter in EOC.

Abstract 2641: Tailored antibody drug conjugate (ADC) therapy depending on a quantity of tumor stroma

Abstract Although many monoclonal antibodies (mAbs) have been already approved for the therapy of cancer, they are usually used in combination with anticancer agents (ACAs), because of limited anti-tumor activity as single agent. Antibody-drug conjugate (ADC), is a promising next generation therapeutic antibody strategy to enhance the cytotoxic effect. Most human solid tumors, however, possess abundant stroma that hinders the distribution of ADC. Also, heterogeneity of the tumor cells complicates the development of ADC therapy based on cell-specific antigens. Moreover, conventional ADC depends upon enzymatic cleavage of the agent following internalization into the cytoplasm or lysosome and the process of cell-uptake can be diminished by a stromal barrier in fibrotic tumors. To overcome these drawbacks, we have developed stroma-targeting ADCs, namely CAST (Cancer stromal targeting) as a novel type of therapy. SN-38 was conjugated to mAbs against collagen 4, or fibrin via ester-bonds. These ADCs bound to collagen 4 or fibrin networks in the stroma. Sustained release of SN-38 from ADCs diffused throughout the tumor tissue, and caused marked damage to both tumor cells and tumor vessels in a pancreatic cancer model. We also prepared SN-38-conjugated anti-CD 20 mAb via carbamate-bond as a conventional ADC. This cell-targeting ADC enabled SN-38 to be released by a carboxylesterase inside of the tumor cell following internalization and showed strong anti-tumor activity against malignant lymphoma which is a hypervascular and stroma poor tumor type. Our results indicate that the conjugate-design, in parallel with the choice of targeting antibodies, should be selected to maximize the therapeutic effect in each individual tumor depending upon the quantity of its stromal component. We will present data on this novel tailored antibody drug conjugate (ADC) therapy and discuss our development strategy for its clinical use. [1] Matsumura Y, Maeda H. A new concept for macromolecular therapeutics in cancer chemotherapy: mechanism of tumoritropic accumulation of proteins and antitumor agent smancs. Cancer Res. 46:6387-92. 1986. [2] Yasunaga M, Manabe S, Matsumura Y. New concept of cytotoxic immunoconjugate therapy cancer-induced fibrin clots. Cancer Sci. 102:1396-1402, 2011. [3] Yasuanga M, Manabe S, Tarin D, Matsumura Y. Cancer-stroma targeting therapy by cytotoxic immunoconjugate bound to the collagen 4 network in the tumor tissue. Bioconjugate Chem.22:1776-1783, 2011. [4] Matsumura Y. Cancer stromal targeting (CAST) therapy.Adv Drug Deliv Rev. 64:710-719, 2012. [5] Yasuanga M, Manabe S, Tarin D, Matsumura Y. Tailored immunoconjugate therapy depending on a quantity of tumor stroma. Cancer Sci. 104:231-7, 2013. [6] Hisada Y, Yasunaga M, Hanaoka S, Saijou S, Sugino T, Tsuji A, Saga T, Tsumoto K, Manabe S, Kuroda J, Kuratsu J, Matsumura Y. Discovery of an uncovered region in fibrin clots and its clinical significance. Sci Rep. 3:2604, 2013. Citation Format: Masahiro Yasunaga, Shino Manabe, David Tarin, Yasuhiro Matsumura. Tailored antibody drug conjugate (ADC) therapy depending on a quantity of tumor stroma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2641. doi:10.1158/1538-7445.AM2014-2641

Abstract P1-06-04: The predictive value of tumor-stroma ratio for radiological and pathological response to neoadjuvant chemotherapy in breast cancer (BC): A Dutch breast cancer trialists’ group (BOOG) side-study

Abstract Background Intra-tumoral stroma interacts with tumor cells and has a profound effect on tumor behavior. The tumor-stroma ratio (TSR) is of prognostic value in BC and other types of solid tumors. However, the predictive value of this parameter for achieving pathological complete response (pCR) after neoadjuvant chemotherapy is unknown. Methods We evaluated the relation between TSR and neoadjuvant treatment response in a retrospective cohort of 69 patients (pts) treated with various regimens of neoadjuvant chemotherapy at our institution who were diagnosed with BC between 1991 and 2007 and of whom radiological response was recorded. The percentage of intra-tumoral stroma was visually estimated on diagnostic sections from primary tumor tissue by two observers. The cut-off point between stroma-rich and stroma-poor tumors was set to 50% (as determined in previous investigations). These results were validated in a cohort from the NEOZOTAC trial: a national, multicenter, randomized study comparing the efficacy of TAC (docetaxel, adriamycin and cyclophosphamide i.v. day 1) chemotherapy with or without zoledronic acid 4 mg i.v., q 3 weeks, 6 times in 250 pts with stage II/III, measurable, HER2-negative BC. Radiological response (complete or partial) was evaluated following RECIST 1.1 criteria. pCR was centrally revised and defined as absence of residual tumor cells in the original tumor bed. Results In the retrospective cohort (n = 69) 62.3% of the specimens were classified as stroma-rich. In univariate analysis TSR was significantly associated with radiological response (76.0% stroma-poor vs. 48.8% stroma-rich, P = 0.03). This finding persisted after multivariate analysis for T-status, N-status and ER-status (Odds Ratio [OR] 0.17, 95% C.I.: 0.04-0.78). In the validation set, in which 47.9% of the specimens were stroma-rich (211 cases evaluated), TSR did not predict for radiological response (79.5% stroma-poor vs. 79.2%, P = 0.96). However, when validation data were split on basis of ER-status, TSR was a significant and independent predictor for radiological response in ER-negative pts. (89.5% vs. 50%, P = 0.048, 95% C.I.: 0.01 - 0.98). In the validation set, TSR predicted for pCR with greater pCR rates in stroma-poor tumors (P = 0.03, 22.7% vs 10.3%). Final response results of the pilot and the enlarged sample size of all 250 pts of the validation set will be presented. Conclusions TSR might be a marker for radiological and pathological response to neoadjuvant chemotherapy, especially for the ER- tumor subgroup. Considering the simplicity and low cost of TSR assessment, it should be further evaluated and will be prospectively studied in the next neoadjuvant chemotherapy trial of the BOOG. Contact information: Dr. J.R. Kroep, M.D., Ph.D., Department of Medical Oncology, email:j.r.kroep@lumc.nl or T.J.A. Dekker, MSc. Department of Surgery and Medical Oncology, email: t.j.a.dekker@lumc.nl or LUMC datacenter, Department of Surgery, phone +31(0)71-5263500, fax +31(0)71-5266744, email: datacenter@lumc.nl, Leiden University Medical Center (LUMC), Leiden, The Netherlands. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-04.

Tumor–stroma ratio is an independent predictor for survival in early cervical carcinoma

ObjectiveTumor–stroma ratio (TSR) has recently been identified as an independent prognostic parameter for several solid tumors. The aim of the present study was to evaluate the prognostic role of TSR in early cervical cancer. MethodsA cohort of 184 patients who had surgery for early stage cervical cancer (FIGO [International Federation of Gynecology and Obstetrics] stages IA2–IIA) were enrolled in this study. TSR was estimated on hematoxylin–eosin-stained tissue sections from the most invasive part of the primary tumor. Patients with less than 50% stroma were classified as stroma-poor and patients with ≥50% stroma were classified as stroma-rich. The relationship between TSR and survival time was statistically analyzed. ResultsThe disease-free survival and overall survival rates were 88.44% and 92.52%, respectively, in the stroma-poor group, and 62.16% and 70.27%, respectively, in the stroma-rich group. Both the disease-free and overall survival rates in the stroma-poor group were significantly better than those in the stroma-rich group (p=0.001). In a multivariate analysis, TSR was further confirmed as a significant prognostic factor for disease-free survival (hazard ratio 3.125; p=0.005) and overall survival (hazard ratio 3.464; p=0.003), independent of tumor size, FIGO stage and lymph node metastasis. ConclusionOur study identified that TSR was an independent prognostic factor of early cervical cancer. Patients with stroma-rich tumors had worse prognosis and higher risk of relapse compared with those with stroma-poor tumors. Considering its simplicity and availability for conventional clinical pathology, TSR may serve as a new prognostic histological characteristic in early cervical cancer.

Tailored immunoconjugate therapy depending on a quantity of tumor stroma

The purpose of this study was to clarify the appropriate combination of targeting antibody and conjugate-design of anti-tumor immunoconjugate depending on a quantity of tumor stroma. Most human solid tumors including pancreatic cancer (PC) forming hypovascular and stroma-rich tumor hinders the penetration of monoclonal antibodies (mAbs) into the cells, and that leads to failure of the conventional cell-targeting immunoconjugate strategy. To overcome this drawback, SN-38 as topoisomerase 1 inhibitor was conjugated to a mAb to collagen 4, a plentiful component of the tumor stroma via ester-bond. The immunoconjugate, which was able to release SN-38 in physiological condition outside the cells, was effective to stroma-rich PC-tumor. On the other hand, anti-CD 20 mAb-PEG-SN-38 via carbamate-bond as conventional immunoconjugate, enabled SN-38 to be released by a carboxylesterase inside of the tumor cell following the internalization, showed strong anti-tumor activity against malignant lymphoma as hypervascular and stroma-poor tumor. The conjugate-design, in parallel with the choice of targeting antibodies, should be selected to maximize the therapeutic effect in each individual tumor having a distinct stromal structure.

Cancer-Stroma Targeting Therapy by Cytotoxic Immunoconjugate Bound to the Collagen 4 Network in the Tumor Tissue

Some cytotoxic immunoconjugates have been approved for malignant lymphoma, a representative of hypervascular and stroma-poor tumors. However, many human solid tumors possess abundant intercellular stromata that prevent diffusion of cancer cell-specific monoclonal antibodies (mAb) and become a barrier preventing immunoconjugates from directly attacking cancer cells. Here we show the successful development of a new strategy that overcomes this drawback and achieves a highly localized concentration of a topoisomerase I inhibitor, SN 38, by conjugating it via an ester bond to a mAb targeted against collagen 4, a plentiful component of the tumor stroma. Poly(ethylene glycol) (PEG) was utilized as a spacer, close to each bond, to maintain stability in the blood. Immunoconjugates selectively extravasated from leaky tumor vessels and minimally from normal vessels because the immunoconjugates are too large to pass through normal vessel walls. Stroma-targeting immunoconjugates bound to the stroma to create a scaffold, from which sustained release of cytotoxic agent occurred and the agent subsequently diffused throughout the tumor tissue to damage both tumor cells and vessels. Cancer-stroma-targeting immunoconjugate therapy was thus validated as a new modality of oncological therapy, especially for refractory, stromal-rich cancers.