Evaluating morphological features for predicting microsatellite instability status in colorectal cancer.

Background: Colorectal cancer (CRC) is one of the commonest cancers worldwide, with incidence rates in India being around 4%. It is a heterogeneous disease with multiple established prognostic factors. Ten to fifteen percent originate from microsatellite instability (MSI) pathway, characterized by defect in mismatch repair (MMR) gene. Identification of MMR defective protein is relevant for diagnosis, prognosis, and prediction. Certain clinical and histological features are known to be associated with defective MMR genes. The objectives of this study are to find the prevalence of MSI in CRC to identify features associated with MSI and assess the value of histopathology in predicting MSI. Methods: We evaluated various clinical and histological parameters for identifying prognostically favorable colon cancers in a tertiary hospital. One hundred fifty colon cancers were evaluated, and MSI status was correlated with clinicopathologic variables. Results: The prevalence of MSI in CRC was found to be 11.3%. The factors associated with MSI were tumor differentiation, stage, tumor site, tumor size, tumor-infiltrating lymphocytes, Crohn's-like lymphoid reaction, and dirty necrosis. We have defined a "P" score for prediction of MSI using the clinicohistological parameters, which could be used to select patients who are to be tested for MSI. Conclusion: Assessment of clinical and histopathological features will help in patient stratification and selection of patients for MSI testing. The evaluation is economical, reproducible, and easy to apply.

Clinicopathological spectrum and treatment outcome of idiopathic steroid-resistant nephrotic syndrome in children at a tertiary care center.

Background: Idiopathic steroid-resistant nephrotic syndrome (iSRNS) is a common problem in pediatric nephrology. About 10%-20% of children with nephrotic syndrome have iSRNS and almost 50 percent progress to end-stage renal disease. Very few studies have tried to study the histopathological spectrum, correlate clinical features, renal biopsy patterns and treatment outcome in children presenting with iSRNS in India. In this study, we compared the histopathologic distribution of different subtypes of glomerular morphologic patterns in iSRNS and the clinical and biochemical parameters at the time of diagnosis and outcome of patients after immunosuppressive therapy. Methods: It is a retrospective cross-sectional study involving review of records of all children with iSRNS presenting to our pediatric nephrology OPD who underwent renal needle biopsy and followed-up for a period of atleast six months post biopsy. Histopathological subtypes were correlated with clinical features (viz. age of onset, gender, oliguria, microscopic hematuria, hypertension, serum creatinine at presentation, serum total protein, serum albumin, 24 h urine protein, persistent proteinuria after 12 weeks of calcineurin inhibitor therapy, and progress to end stage renal disease (ERSD), if any, outcome. Result: It was found that minimal change disease (MCD) was overall the most common cause of iSRNS. These patients have a significantly greater incidence of remission with immunosuppression as compared with focal segmental glomerulosclerosis (FSGS) and IgA nephropathy subgroup. Conclusion: Kidney biopsy is of prognostic value in children with iSRNS. The prognosis of children with SRNS owing to MCD is much better than with other nephropathy.

Do extraglomerular microvasculature and mesenchymal interstitial cell proliferation indicate a stable course of lupus nephritis?

Background: Lupus Nephritis (LN) is a major and frequent manifestation of Systemic Lupus Erythematosus (SLE), an autoimmune disease. Renal biopsy has a pivotal role in the diagnosis, prognosis, and management of the LN. The aim of this study was to count the mesenchymal interstitial cells utilizing CD34 immunohistochemistry (IHC) and morphometric analysis, correlate them with clinical parameters, class, activity, and chronicity indices and see if it can predict the course of the disease. Methods: A total of 32 renal biopsy blocks were analyzed by H&E stain, special stains, and CD34 IHC. Microvasculature density and interstitial stem cells were highlighted by CD34. These were then counted using a previously standardized computerized digital photomicrograph system (Dewinter Optical Inc) and manual count, respectively. Results: Out of the 32 cases, Lupus class 3 comprised of 11 (34.38%) cases, class 4 comprised of 16 (50%) cases, and mixed class 4 + 5 had 5 (15.62%) cases. It was found that CD34 expression in the microvasculature (for both microvascular density and mean vascular lumen diameter) decreased in patients of Lupus Nephritis with higher disease activity (p < 0.05). Although not statistically significant, the number of interstitial stem cells increased with lower disease activity. A statistical significance was found between serum total protein, serum albumin, and serum creatinine among the three groups of LN. Conclusion: Immunohistochemical staining of renal biopsy with CD34 may be used as a surrogate marker of disease activity in Lupus Nephritis patients.

Utility of glomerular morphometry in diagnosing pediatric renal disease.

BACKGROUND: Morphometry has now become a useful adjunct to the diagnostic armamentarium of light, immunofluorescence, and electron microscopy, as it provides a deep insight into quantitative parameters of nephropathies. There has been a limited study on its utility especially in diagnosing pediatric renal diseases. This study is probably the first in India to assess the contribution of this diagnostic modality in pediatric renal disease to the best of authors' knowledge. METHODS: It's a retrospective cross-sectional study covering a period of 05 years at a tertiary care hospital. The study includes 28 cases of pediatric (age till 14 years) nephropathies. The diseases were divided into two groups-nephrotic presentation and nephritic presentation. Glomerular morphometry was performed and mean was calculated for Bowman's capsule area, glomerular capillary tuft area, and Bowman's space area; for the three groups, respectively. Renal parameters serum creatinine, blood urea, 24 h urine protein were studied along with hemoglobin and serum cholesterol for the cases. Data were analyzed using SPSS software, version 25, for one-way ANOVA comparing mean in the three groups. RESULTS: We found a positive and significant correlation between Bowman's capsule area with proteinuria, blood urea, and serum creatinine. There was positive and significant correlation between glomerular capillary tuft area and serum creatinine and Bowman's space area and proteinuria in both the groups. CONCLUSION: Glomerular morphometry may contribute to the diagnosis of some glomerulopathies and the association between glomerular morphometric parameters and laboratory data may promote better understanding of the prognosis of these patients.

Study of platelet indices in pregnancy-induced hypertension.

BACKGROUND: Hypertension encountered during pregnancy could be the first sign of a preexisting pathology that can significantly attribute to unfavorable maternal, fetal, and neonatal outcomes. Resolving hypertensive disorders at an early age may not alter the course and proficiency of the disease, but timely detection and treatment can not only prevent hypertensive crisis but also alter unfavorable fetal outcomes. Ipso facto, an early cataloging plays an essential role in predicting the outcome of pregnancy, both for mother and baby. Platelet indices correlate with functional status of platelets and are an emerging risk marker for detecting an impending adverse outcome in pregnancy-induced hypertension (PIH). The aim of this study was to analyze the consociation between platelet indices and severity of PIH. METHODS: A prospective hospital-based study was undertaken on 100 cases diagnosed with PIH (preeclampsia [PE; 88 cases] and eclampsia [12 cases and 100 controls]). RESULTS: Most cases occurred in the age group of 22-26 years (43.3%) and in primigravidae (55.8%). Analysis of platelet volume indices (PVI) indicated mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large cell ratio (P-LCR) as significant risk factors for developing hypertensive crisis. This was in concordance with the elevated blood pressures. CONCLUSION: The study concludes that platelet indices are raised in patients who have PIH as compared with normal pregnancies.

Nevus Lipomatosis Cutaneous Superficialis - A clinicopathologic study of the solitary type.

BACKGROUND: Nevus Lipomatosis Cutaneous Superficialis (NLCS) is a rare, benign hamartomatous lesion characterized by the ectopic presence of mature adipocytes in the reticular dermis not associated with the underlying subcutaneous tissue. Two clinical forms-classical and solitary occur. The solitary form is relatively uncommon, due to which these lesions are commonly clinically misdiagnosed. The aim was to study the clinical and histopathological features of the solitary type of NLCS. METHODS: Seven cases of histopathologically documented solitary type of NLCS which presented at our institute between August 2013 and June 2014 were retrospectively analysed for clinical data and histopathological findings. Haematoxylin and Eosin (H&E) and Elastic Van Gieson (EVG) stained slides were studied in all cases. RESULTS: Mean age of the patients was 42.5 years. These lesions were more common in adult females (5/7). Thigh was the commonest location (4/7). The mean duration of these lesions was 2.0 years. Clinical diagnosis was papilloma (4/7) and acrochordon (3/7). Histopathology revealed the presence of varying amounts of mature ectopic adipocytes in the dermis located around dilated, ectactic blood vessels. Disorganised dermal collagen bundles and atrophic pilosebaceous units were seen. CONCLUSION: This study is a first from the Indian subcontinent and highlights the need for awareness of this rare clinical condition both by the dermatologists and the surgeons. Histopathology is essential for diagnosis as clinically they may mimic papillomas or skin tags. An early diagnosis may permit a more conservative resection of the tumour.

Inflammatory Myofibroblastic Tumor of the Oral Cavity. A Great Mimicker.

Inflammatory myofibroblastic tumor (IMT) is a seldom-described tumor of indefinite etiology and pathogenesis. It occurs primarily in the lungs, but has occurred in other extra-pulmonary sites. Histologically, these lesions appear as an inflammatory infiltrate within a variably myofibrotic background. Current evidence shows that inflammatory myofibroblastic tumors are neoplastic processes resulting from chromosomal translocations that frequently cause an overexpression of ALK kinase, often assessed using immunohistochemical studies. Currently, the biological behavior of oral IMT is still uncertain. This article illustrates the clinical, histological and operative features of a case of IMT of the oral cavity.

Pseudohyperplastic variant of adenocarcinoma as a component of α-methyl-CoA-racemase (AMACR negative) carcinosarcoma of the prostate.

Carcinosarcoma (CS) or Sarcomatoid carcinoma (SC) of the prostate is a very rare malignant tumor of the prostate having an aggressive clinical course and dismal prognosis. The adenocarcinomatous element is usually of the acinar type and closely admixed with a sarcomatous component. We report a case of α-methyl-CoA-racemase (AMACR)-negative pseudohyperplastic variant of adenocarcinoma in CS. To the best of our knowledge, there have been no published case reports of this variant in CS till date. An accurate diagnosis is essential as this uncommon, aggressive cancer has limited therapeutic options.

Contact Endoscopy of mucosal lesions of oral cavity - Preliminary experience.

BACKGROUND: Contact Endoscopy is a non invasive tool to visualise alterations in cell architecture in vivo. In this study we investigated the diagnostic accuracy of Contact Endoscopy in detecting malignancy in oral mucosal lesions. METHODS: 76 patients with oral mucosal lesions requiring biopsy were included. Contact Endoscopy was performed by Otolaryngologist before biopsy and findings recorded. The lesion was then biopsied and sent for histopathological examination by Pathologist who was blinded to Contact Endoscopy findings. Findings of Contact Endoscopy were compared with histopathological findings taking the latter as the gold standard. Two biopsies were reported as 'inconclusive' on histopathological examination and hence excluded from the final analysis. Data of the remaining 74 patients is presented here. RESULTS: Clinically lesions were diagnosed as ulcero-proliferative lesions in 34 patients, Leukoplakia in 19, Erythroplakia in 9, Lichen planus in 5 and Submucous fibrosis in 7 patients. Histopathological examination revealed presence of malignancy in 97.06% of ulcero-proliferative mucosal lesions, 10.53% of leukoplakia and 33.33% of erythroplakia while corresponding figures on Contact Endoscopy were 94.12%, 5.26% and 11.11% respectively. No malignancy was detected in lichen planus and submucous fibrosis by either technique. When compared with histopathological examination, CE showed sensitivity of 84.21%, specificity of 94.44% and accuracy of 89.19%. No adverse effects on the patients were seen due to the procedure or stain. CONCLUSION: Contact Endoscopy may be useful in determining cellular structure in vivo without biopsy to detect oral malignancy early. Further studies are suggested.

Meeting proceedings of the 43rd Indian Association for Cancer Research (IACR).

The 43rd Annual Conference of the Indian Association of Cancer Research (IACR) was held between 19th and 22nd January 2024 at the Indian Institute of Education and Research (IISER), Pune, India. Cancer is the second leading cause of death globally; efforts have been made to understand and treat this deadly disease for several decades. The 43rd IACR, organised by Mayurika Lahiri, Kundan Sengupta, Nagaraj Balasubramanian, Mridula Nambiar, Krishanpal Karmodiya, and Siddhesh Kamat, highlighted recent advances in cancer research, with implications in therapeutics at the forefront of the discussions. The meeting proved to be a promising platform for cancer researchers ranging from graduate and postdoctoral students to subject experts in varied aspects of cancer biology to showcase their research, ideate with their peers, and form collaborations.

Study of the association of the known prognostic variables with EGFR expression in head and neck squamous cell carcinomas.

Context: : Head and neck squamous cell carcinomas (HNSCCs) are the sixth most frequent malignancy in the world. Epidermal growth factor receptors (EGFRs) are members of Erb B family of receptors. EGFR is known to act as a driver of tumorigenesis in various carcinomas. Over expression of EGFR in HNSCC is associated with poor prognosis and resistance to radiotherapy. It is a useful prognostic marker, marker for response to therapy, and also a therapeutic target. Aim: To study the association of the known prognostic variables with EGFR expression in HNSCCs and to correlate it with the clinical outcome. Settings and Design: Cross-sectional observational study. Materials and Methods: A total of 170 patients of HNSCC were evaluated for EGFR expression and followed up for at least two years, with correlation of EGFR expression with various histopathological factors and their clinical outcome. Statistical Analysis Used: : Chi-square test. Results: The expression of EGFR in HNSCC in this study population was 88.82%. Statistical significance was noted between EGFR reactivity and age of the patient, its histological grade and perineural invasion. Statistical significance was also noted between EGFR reactivity and recurrence of malignancy as well as the site of recurrence. Conclusion: EGFR expression in patients with HNSCC is a poor prognostic biomarker and has a comparatively lower survival outcome as compared to non-EGFR expressing HNSCC cases. Hence, it will be helpful for all those patients diagnosed with HNSCC to ideally undergo an additional EGFR immunohistochemical evaluation, which, in turn, will help the oncologists in management of the tumor with anti-EGFR therapy combined with radiotherapy, to obtain a better response and a survival outcome.

The systemic immune-inflammation index in predicting sepsis mortality.

BACKGROUND: The systemic immune-inflammation index (SII) is a novel parameter and its role in the prognosis of sepsis has never been explored previously. METHODS: We retrospectively assessed 267 patients with blood-culture confirmed sepsis. Clinical and laboratory data recorded at intensive care unit (ICU) admission were analyzed. Outcomes of interest included in-hospital mortality and length-of-stay (LOS) in the ICU. Sequential Organ Failure Assessment (SOFA) scores, SII, neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were calculated. Multivariable regression analysis was used to identify independent predictors of LOS and mortality. Area under receiver operator characteristic (AUROC) curves were used to determine optimum cutoffs, and the incremental effect of SII on the SOFA score was assessed using model discrimination and calibration properties. RESULTS: There were 76 (28.5%) non-survivors. SII, NLR, and PLR were independent predictors of sepsis mortality, with adjusted odds ratios of 1.51 (1.24-1.84), 1.67 (1.30-2.13) and 1.24 (1.11-1.39). SII and SOFA score were independent predictors of LOS. SII had an AUROC of 0.848, and the optimum cutoff was 564 with a sensitivity and specificity of 85.5% and 71.2%. The addition of SII to the model had a significant incremental effect on the predictive ability of SOFA score (Net Reclassification Index = 0.084, P = 0.025; Integrated Discrimination Index = 0.056, P = 0.001). CONCLUSION: The SII is an inexpensive parameter that can be used in addition to clinical sepsis scores to improve the accuracy of patient assessment.

Evaluation of Number Density of Tumor-Associated Macrophages by Immunohistochemistry and Semiquantitative Scoring in Invasive Breast Cancer: An Indian Study.

Context: Tumor microenvironment is emerging as a critical factor for progression of breast cancer. Tumor-associated macrophages (TAMs) play an important role in promoting tumor growth. Aim: This study was aimed at correlation of number density (ND) of TAMs with invasive ductal carcinoma (IDC) grading utilizing an image morphometric technique. We also sought to compare the TAMs and ND in the tumoral area and stromal region. We also explored the relationship between the clinical and pathological prognostic parameters. Subjects and Methods: The study included 75 cases of IDC that had undergone modified radical mastectomy. The Institutional Ethics Committee approved the study. Samples were classified as Grade 1, 2, and 3. Cases were graded as per the modified Bloom and Richardson criterion. Mean with standard deviation was calculated for each group. We utilized CD68 and CD163 immunostained sections for determining the ND of TAMs. TAMs were evaluated using computerized digital photomicrograph system with image analyzing software. ND was defined as the number of TAMs in total number of TAMs in five high-power fields/total area of five fields. ND was calculated separately in tumor and tumor stroma (TS). Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2/neu (HER2/neu) were scored in accordance with recommendations. Ki-67 was scored as per the recommended guidelines. Statistical Analysis Used: Data were tabulated in Microsoft Excel. SPSS version 20.0 (IBM Corp., Armonk, NY, USA) was used for statistical analysis. To determine the relationship between macrophage density and clinicopathologic parameters, we used the independent t-test. To determine the differences in the parameters, analysis of variance (ANOVA) was utilized. Results: Age of the patients ranged from 34 to 58 years (mean: 55.5). One-way ANOVA between various grades of tumor indicating significant differences in terms of CD68 and CD163 densities in tumor and stroma (P < 0.0001). i.e., significant increased density of CD68 and CD163 was observed in Grade 3 tumor as compared to other two groups. A greater histological grade, ER, PR negative status, and a high Ki-67 index were all associated with TAM ND. There was no relation to HER2/neu status. Result of unpaired t-test indicates increased density in stroma as compared to tumor among various grades of IDC. Conclusions: We analyzed images with a software using photographs of the stained slides. This helped in quantitative analysis of TAMs on the CD68 and CD163 stained sections. This approach standardizes and reproducibly counts TAMs per unit area. We found significant difference between the number densities of TAMs in grades of invasive breast carcinoma. There were statistically significant differences in numerical densities of TAMs with ER, PR negativity, and Ki-67. There was no correlation with HER2/neu. Densities of CD68 and CD163 densities are more prevalent in TS as compared to intratumoral region.

Perception without preconception: comparison between the human and machine learner in recognition of tissues from histological sections.

Deep neural networks (DNNs) have shown success in image classification, with high accuracy in recognition of everyday objects. Performance of DNNs has traditionally been measured assuming human accuracy is perfect. In specific problem domains, however, human accuracy is less than perfect and a comparison between humans and machine learning (ML) models can be performed. In recognising everyday objects, humans have the advantage of a lifetime of experience, whereas DNN models are trained only with a limited image dataset. We have tried to compare performance of human learners and two DNN models on an image dataset which is novel to both, i.e. histological images. We thus aim to eliminate the advantage of prior experience that humans have over DNN models in image classification. Ten classes of tissues were randomly selected from the undergraduate first year histology curriculum of a Medical School in North India. Two machine learning (ML) models were developed based on the VGG16 (VML) and Inception V2 (IML) DNNs, using transfer learning, to produce a 10-class classifier. One thousand (1000) images belonging to the ten classes (i.e. 100 images from each class) were split into training (700) and validation (300) sets. After training, the VML and IML model achieved 85.67 and 89% accuracy on the validation set, respectively. The training set was also circulated to medical students (MS) of the college for a week. An online quiz, consisting of a random selection of 100 images from the validation set, was conducted on students (after obtaining informed consent) who volunteered for the study. 66 students participated in the quiz, providing 6557 responses. In addition, we prepared a set of 10 images which belonged to different classes of tissue, not present in training set (i.e. out of training scope or OTS images). A second quiz was conducted on medical students with OTS images, and the ML models were also run on these OTS images. The overall accuracy of MS in the first quiz was 55.14%. The two ML models were also run on the first quiz questionnaire, producing accuracy between 91 and 93%. The ML models scored more than 80% of medical students. Analysis of confusion matrices of both ML models and all medical students showed dissimilar error profiles. However, when comparing the subset of students who achieved similar accuracy as the ML models, the error profile was also similar. Recognition of 'stomach' proved difficult for both humans and ML models. In 04 images in the first quiz set, both VML model and medical students produced highly equivocal responses. Within these images, a pattern of bias was uncovered-the tendency of medical students to misclassify 'liver' tissue. The 'stomach' class proved most difficult for both MS and VML, producing 34.84% of all errors of MS, and 41.17% of all errors of VML model; however, the IML model committed most errors in recognising the 'skin' class (27.5% of all errors). Analysis of the convolution layers of the DNN outlined features in the original image which might have led to misclassification by the VML model. In OTS images, however, the medical students produced better overall score than both ML models, i.e. they successfully recognised patterns of similarity between tissues and could generalise their training to a novel dataset. Our findings suggest that within the scope of training, ML models perform better than 80% medical students with a distinct error profile. However, students who have reached accuracy close to the ML models, tend to replicate the error profile as that of the ML models. This suggests a degree of similarity between how machines and humans extract features from an image. If asked to recognise images outside the scope of training, humans perform better at recognising patterns and likeness between tissues. This suggests that 'training' is not the same as 'learning', and humans can extend their pattern-based learning to different domains outside of the training set.

Role of CD34, vascular endothelial growth factor, and p53 in neoangiogenesis as correlated with stage of disease in colorectal carcinoma.

BACKGROUND: Angiogenesis is critical for the growth of colorectal carcinoma (CRC). Vascular endothelial growth factor is the most important angiogenic growth factor. METHOD: Fifty cases of CRC operated at INHS Asvini were studied by using immunohistochemical labelling of the tumours by using CD34, p53, and vascular endothelial growth factor (VEGF). RESULTS: Out of the 50 cases, 31 (62%) were positive for p53; of which 80.7% showed high expression. Significant staining (> 20% tumour cells showing positivity) was seen in 33 patients (66%), while 34% were negative. Of the 33 positive cases, 57.58% showed high-grade VEGF positivity. CONCLUSION: Vascular endothelial growth factor correlated significantly with the stage and grade of disease. Intra tumours microvessel density as calculated from CD34 expression increased with the stage and grade of the CRC.

Platelet Indices and Their Kinetics Predict Mortality in Patients of Sepsis.

Platelet indices are inexpensive, easily accessible parameters and potentially useful prognostic indicators in sepsis. In this study we explore the differences in platelet indices and their kinetics between sepsis survivors and non-survivors. A retrospective cohort-study of 97 cases of culture-positive sepsis at a tertiary-care center in North India. Demographics, clinical and laboratory parameters at admission were assessed. Platelet count (PLT), mean-platelet-volume (MPV), platelet-distribution-width (PDW) and plateletcrit (PCT) on admission, and third, fifth and last days of hospitalization were analyzed. Fractional change in platelet indices (ΔMPV72h, ΔPDW72h, ΔPCT72h, and ΔPLT72h) by day-3 were calculated. Unpaired and paired t-tests were used to compare survivors with non-survivors, and to study the change in platelet indices with time. Logistic regression was used for multivariate analysis. ROC-curves and optimum cut-offs to predict mortality were obtained. There were 64 survivors. Non-survivors had significantly higher ΔMPV72h, ΔPDW72h, day-1 MPV and PDW, and lower ΔPLT72h. MPV and PDW increased, and PLT decreased with time among non-survivors. Trends were reversed in survivors. Only MPV and PDW showed significant change by day-3. Both were independent predictors of mortality on multivariate analysis, alongside ΔMPV72h and ΔPLT72h. On ROC analysis, MPV, PDW, ΔMPV72h, ΔPDW72h and ΔPLT72h effectively predicted mortality. Cut-off for MPV was 10.25 fL (sensitivity = 93.9%, specificity = 60.9%), and PDW, 12.6% (sensitivity = 84.8%, specificity = 51.6%). A rise in MPV and a fall in PLT was associated with mortality in this study. MPV and PDW values at admission are effective predictors of mortality and may be used in conjunction with traditional parameters.

Tumor refractoriness to anti-VEGF treatment is mediated by CD11b+Gr1+ myeloid cells.

Vascular endothelial growth factor (VEGF) is an essential regulator of normal and abnormal blood vessel growth. A monoclonal antibody (mAb) that targets VEGF suppresses tumor growth in murine cancer models and human patients. We investigated cellular and molecular events that mediate refractoriness of tumors to anti-angiogenic therapy. Inherent anti-VEGF refractoriness is associated with infiltration of the tumor tissue by CD11b+Gr1+ myeloid cells. Recruitment of these myeloid cells is also sufficient to confer refractoriness. Combining anti-VEGF treatment with a mAb that targets myeloid cells inhibits growth of refractory tumors more effectively than anti-VEGF alone. Gene expression analysis in CD11b+Gr1+ cells isolated from the bone marrow of mice bearing refractory tumors reveals higher expression of a distinct set of genes known to be implicated in active mobilization and recruitment of myeloid cells. These findings indicate that, in our models, refractoriness to anti-VEGF treatment is determined by the ability of tumors to prime and recruit CD11b+Gr1+ cells.