ACT-Discover: identifying karyotype heterogeneity in pancreatic cancer evolution using ctDNA

BACKGROUND

Liquid biopsies and the dynamic tracking of somatic mutations within circulating tumour DNA (ctDNA) can provide insight into the dynamics of cancer evolution and the intra-tumour heterogeneity that fuels treatment resistance. However, identifying and tracking dynamic changes in somatic copy number alterations (SCNAs), which have been associated with poor outcome and metastasis, using ctDNA is challenging. Pancreatic adenocarcinoma is a disease which has been considered to harbour early punctuated events in its evolution, leading to an early fitness peak, with minimal further subclonal evolution.

METHODS

To interrogate the role of SCNAs in pancreatic adenocarcinoma cancer evolution, we applied whole-exome sequencing of 55 longitudinal cell-free DNA (cfDNA) samples taken from 24 patients (including 8 from whom a patient-derived xenograft (PDX) was derived) with metastatic disease prospectively recruited into a clinical trial. We developed a method, Aneuploidy in Circulating Tumour DNA (ACT-Discover), that leverages haplotype phasing of paired tumour biopsies or PDXs to identify SCNAs in cfDNA with greater sensitivity.

RESULTS

SCNAs were observed within 28 of 47 evaluable cfDNA samples. Of these events, 30% could only be identified by harnessing the haplotype-aware approach leveraged in ACT-Discover. The exceptional purity of PDX tumours enabled near-complete phasing of genomic regions in allelic imbalance, highlighting an important auxiliary function of PDXs. Finally, although the classical model of pancreatic cancer evolution emphasises the importance of early, homogenous somatic events as a key requirement for cancer development, ACT-Discover identified substantial heterogeneity of SCNAs, including parallel focal and arm-level events, affecting different parental alleles within individual tumours. Indeed, ongoing acquisition of SCNAs was identified within tumours throughout the disease course, including within an untreated metastatic tumour.

CONCLUSIONS

This work demonstrates the power of haplotype phasing to study genomic variation in cfDNA samples and reveals undiscovered intra-tumour heterogeneity with important scientific and clinical implications. Implementation of ACT-Discover could lead to important insights from existing cohorts or underpin future prospective studies seeking to characterise the landscape of tumour evolution through liquid biopsy.

Abstract CT225: A randomized trial of integrated genomics, organoids and avatar mouse models for personalized treatment of pancreatic cancer

Background: Pancreatic adenocarcinoma (PDAC) remains one of the most lethal cancers. This study aimed to compare the efficacy of a comprehensive approach to precision medicine, including genomic and bio-informatic analysis of tumor biopsies, as well as modeling of the disease in Avatar Mouse Models and Patient Derived Organoids (PDO) to conventional treatment.

Method: We conducted a prospective, randomized, multicenter clinical trial in which, patients with newly diagnosed advanced PDAC were randomized to either a personalized medicine approach or to a conventional treatment in a 2:1 ratio. Patients randomized to the conventional arm were treated with standard of care therapy. Patients randomized to the experimental arm underwent a tumor biopsy to determine their genetic status through whole exome sequencing (WES) and to generate an Avatar and PDO model. Personalized treatment was based on the targets identified by genetic and bioinformatic analysis, as well as by phenotypic screening of 40 anticancer agents in the patient derived models after discussion in a molecular committee.

Results: A total 129 PDAC patients with a median age of 62 years old, were enrolled and 122 were included in the analysis. Seventy-eight patients were randomized to the experimental arm and 44 to the conventional one. WES has been performed in 66 patients and in 56 of them potentially actionable pathogenic variants were detected. Experimental models were successfully generated in 28 patients and screened. However, only 4 patients were treated with selected agents. The remaining 52 patients could not be treated according to the results of the study: 73% of them because of premature clinical deterioration, 8% because of delaying in obtaining results due to technical matters and 19% because the recommended treatment was not felt to have adequate data support by the molecular committee. The median overall survival (from the date of randomization until the date of death) was 8,7 months for patients from conventional arm and 8,8 months for patients from experimental arm (not statistically different). The median overall survival (from the date of randomization until the date of death) for the four patients treated according to the results of the study was 19,5 months.

Conclusions: In our study, a full personalized medicine approach did not improve the overall survival of patients with PDAC. Failure to obtain genomic data and models, lack of actionable genetic alterations and targeted agents in living models, and the rapid course of PDAC limited the implementation of precision medicine treatments. Outcome was improved in the 6% of patients in whom a personalized treatment was administered.

Citation Format: Manuel Hidalgo, Francesca Sarno, Laura Medina, Roberto Pazo, Ignacio Juez, Rocío García-Carbonero, Carmen Guillén-Ponce, Jaime Feliú, Carolina Alonso, Jair Tenorio_Castano, Pablo Lapunzina. A randomized trial of integrated genomics, organoids and avatar mouse models for personalized treatment of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT225.

Multiplexed magnetic beads-assisted amperometric bioplatforms for global detection of methylations in nucleic acids

This work reports the first electrochemical bioplatform developed for the multidetection of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in DNA, DNA N6-methyladenine (6mA) and RNA N6-methyladenosine (m6A) methylations at global level. Direct competitive immunoassays were implemented on the surface of magnetic beads (MBs) and optimized for the single amperometric determination of different targets varying in length, sequence and number of methylations on screen-printed carbon electrodes. After evaluating the sensitivity and selectivity of such determinations and the confirmation of no cross-reactivity, a multiplexed disposable platform allowing the simultaneous determination of the mentioned four methylation events in only 45 min has been prepared. The multiplexed bioplatform was successfully applied to the determination of m6A in cellular total RNA and of 5-mC, 5-hmC and 6mA in genomic DNA extracted from tissues. The developed bioplatform showed its usefulness to discriminate the aggressiveness of cancerous cells and between healthy and tumor tissues of colorectal cancer patients.

Amperometric Bioplatforms To Detect Regional DNA Methylation with Single-Base Sensitivity

This work reports the first bioplatform able to determine electrochemically 5-hydroxymethylcytosine (5-hmC) methylation events at localized sites and single-base sensitivity. The described bioplatform relies on a specific antibody (anti-5-hmC), further conjugated with commercial bioreagents loaded with multiple horseradish peroxidase (HRP) molecules, recognizing the epimark in a target DNA, captured through hybridization onto streptavidin-magnetic microbeads (Strep-MBs) modified with a complementary DNA capture probe. The electrochemical detection is performed by amperometry (-0.20 V vs Ag pseudoreference electrode) at disposable screen-printed carbon electrodes (SPCEs) in the presence of H₂O₂/hydroquinone (HQ) upon magnetic capture of the modified MBs onto the SPCE. The use of the commercial bioreagents ProtA-polyHRP₈₀ and Histostar, very scarcely explored so far in electrochemical biosensors, provides high sensitivities for a synthetic target DNA sequence with a unique 5-hmC in the promoter region of MGMT tumor suppressor gene. Amplification factors of 43.6 and 55.2 were achieved using ProtA-polyHRP₈₀ or Histostar, respectively, compared to the conventional secondary antibody labeling. This amplification was crucial to detect methylation events at single-nucleotide resolution achieving limits of detection (LODs) of 23.0 and 13.2 pM, respectively, without any target DNA amplification. The ProtA-polyHRP₈₀-based bioplatform, selected as a compromise between sensitivity and cost per determination, exhibited full discrimination toward the target 5-hmC against the closely related 5-mC. In addition, the bioplatform detected 5-hmC at the regional level (MGMT promoter region) in just 10 ng of genomic DNA (gDNA, ∼2700 genomes) extracted from cancer cells and tissues from colorectal cancer (CRC) patients within 60 min.

Versatile Electroanalytical Bioplatforms for Simultaneous Determination of Cancer-Related DNA 5-Methyl- and 5-Hydroxymethyl-Cytosines at Global and Gene-Specific Levels in Human Serum and Tissues

This paper reports the preparation of versatile electrochemical biosensing platforms for the simple, rapid, and PCR-independent detection of the most frequent DNA methylation marks (5-methylcytosine, 5-mC, and/or 5-hydroxymethylcytosine, 5-hmC) both at global and gene-specific levels. The implemented strategies, relying on the smart coupling of immuno-magnetic beads (MBs), specific DNA probes and amperometric detection at screen-printed carbon electrodes (SPCEs), provided sensitive and selective determination of the target methylated DNAs in less than 90 min with a great reproducibility and demonstrated feasibility for the simultaneous detection of the same or different cytosine epimarks both at global level and in different loci of the same gene or in different genes. The bioplatforms were applied to determine global methylation events in paraffin-embedded colorectal tissues and specific methylation at promoters of tumor suppressor genes in genomic DNA extracted from cancer cells and paraffin-embedded colorectal tissues, and in serum without previous DNA extraction from cancer patients.

Probabilistic graphical models relate immune status with response to neoadjuvant chemotherapy in breast cancer

Breast cancer is the most frequent tumor in women and its incidence is increasing. Neoadjuvant chemotherapy has become standard of care as a complement to surgery in locally advanced or poor-prognosis early stage disease. The achievement of a complete response to neoadjuvant chemotherapy correlates with prognosis but it is not possible to predict who will obtain an excellent response. The molecular analysis of the tumor offers a unique opportunity to unveil predictive factors. In this work, gene expression profiling in 279 tumor samples from patients receiving neoadjuvant chemotherapy was performed and probabilistic graphical models were used. This approach enables addressing biological and clinical questions from a Systems Biology perspective, allowing to deal with large gene expression data and their interactions. Tumors presenting complete response to neoadjuvant chemotherapy had a higher activity of immune related functions compared to resistant tumors. Similarly, samples from complete responders presented higher expression ​​of lymphocyte cell lineage markers, immune-activating and immune-suppressive markers, which may correlate with tumor infiltration by lymphocytes (TILs). These results suggest that the patient's immune system plays a key role in tumor response to neoadjuvant treatment. However, future studies with larger cohorts are necessary to validate these hypotheses.

Clinical relevance of the transcriptional signature regulated by CDC42 in colorectal cancer

CDC42 is an oncogenic Rho GTPase overexpressed in colorectal cancer (CRC). Although CDC42 has been shown to regulate gene transcription, the specific molecular mechanisms regulating the oncogenic ability of CDC42 remain unknown. Here, we have characterized the transcriptional networks governed by CDC42 in the CRC SW620 cell line using gene expression analysis. Our results establish that several cancer-related signaling pathways, including cell migration and cell proliferation, are regulated by CDC42. This transcriptional signature was validated in two large cohorts of CRC patients and its clinical relevance was also studied. We demonstrate that three CDC42-regulated genes offered a better prognostic value when combined with CDC42 compared to CDC42 alone. In particular, the concordant overexpression of CDC42 and silencing of the putative tumor suppressor gene CACNA2D2 dramatically improved the prognostic value. The CACNA2D2/CDC42 prognostic classifier was further validated in a third CRC cohort as well as in vitro and in vivo CRC models. Altogether, we show that CDC42 has an active oncogenic role in CRC via the transcriptional regulation of multiple cancer-related pathways and that CDC42-mediated silencing of CACNA2D2 is clinically relevant. Our results further support the use of CDC42 specific inhibitors for the treatment of the most aggressive types of CRC.

Molecular characterization of breast cancer cell response to metabolic drugs

Metabolic reprogramming is a hallmark of cancer. It has been described that breast cancer subtypes present metabolism differences and this fact enables the possibility of using metabolic inhibitors as targeted drugs in specific scenarios. In this study, breast cancer cell lines were treated with metformin and rapamycin, showing a heterogeneous response to treatment and leading to cell cycle disruption. The genetic causes and molecular effects of this differential response were characterized by means of SNP genotyping and mass spectrometry-based proteomics. Protein expression was analyzed using probabilistic graphical models, showing that treatments elicit various responses in some biological processes such as transcription. Moreover, flux balance analysis using protein expression values showed that predicted growth rates were comparable with cell viability measurements and suggesting an increase in reactive oxygen species response enzymes due to metformin treatment. In addition, a method to assess flux differences in whole pathways was proposed. Our results show that these diverse approaches provide complementary information and allow us to suggest hypotheses about the response to drugs that target metabolism and their mechanisms of action.

Delphi consensus of an expert committee in oncogeriatrics regarding comprehensive geriatric assessment in seniors with cancer in Spain

OBJECTIVES

The aim of this work was to reach a national consensus in Spain regarding the Comprehensive Geriatric Assessment (CGA) domains in older oncological patients and the CGA scales to be used as a foundation for widespread use.

MATERIAL AND METHODS

The Delphi method was implemented to attain consensus. Representatives of the panel were chosen from among the members of the Oncogeriatric Working Group of the Spanish Society of Medical Oncology (SEOM). Consensus was defined as ≥66.7% coincidence in responses and by the stability of said coincidence (changes ≤15% between rounds). The study was conducted between July and December 2016.

RESULTS

Of the 17 people invited to participate, 16 agreed. The panel concluded by consensus that the following domains should be included in the CGA:(and the scales to evaluate them): functional (Barthel Index, Lawton-Brody scale, gait speed), cognitive (Pfeiffer questionnaire), nutritional (Mini Nutritional Assessment - MNA), psychological/mood (Yesavage scale), social-familial (Gijon scale), comorbidity (Charlson index), medications, and geriatric syndromes (urinary and/or fecal incontinence, low auditory and/or visual acuity, presence of falls, pressure sores, insomnia, and abuse). Also by consensus, the CGA should be administered to older patients with cancer for whom there is a subsequent therapeutic intent and who scored positive on a previous frailty-screening questionnaire.

CONCLUSION

After 3 rounds, consensus was reached regarding CGA domains to be used in older patients with cancer, the scales to be administered for each of these domains, as well as the timeline to be followed during consultation.

Comparison of risk classification between EndoPredict and MammaPrint in ER-positive/HER2-negative primary invasive breast cancer

PURPOSE

To compare the concordance in risk classification between the EndoPredict and the MammaPrint scores obtained for the same cancer samples on 40 estrogen-receptor positive/HER2-negative breast carcinomas.

METHODS

Formalin-fixed, paraffin-embedded invasive breast carcinoma tissues that were previously analyzed with MammaPrint as part of routine care of the patients, and were classified as high-risk (20 patients) and low-risk (20 patients), were selected to be analyzed by the EndoPredict assay, a second generation gene expression test that combines expression of 8 genes (EP score) with two clinicopathological variables (tumor size and nodal status, EPclin score).

RESULTS

The EP score classified 15 patients as low-risk and 25 patients as high-risk. EPclin re-classified 5 of the 25 EP high-risk patients into low-risk, resulting in a total of 20 high-risk and 20 low-risk tumors. EP score and MammaPrint score were significantly correlated (p = 0.008). Twelve of 20 samples classified as low-risk by MammaPrint were also low-risk by EP score (60%). 17 of 20 MammaPrint high-risk tumors were also high-risk by EP score. The overall concordance between EP score and MammaPrint was 72.5% (κ = 0.45, (95% CI, 0.182 to 0.718)). EPclin score also correlated with MammaPrint results (p = 0.004). Discrepancies between both tests occurred in 10 cases: 5 MammaPrint low-risk patients were classified as EPclin high-risk and 5 high-risk MammaPrint were classified as low-risk by EPclin and overall concordance of 75% (κ = 0.5, (95% CI, 0.232 to 0.768)).

CONCLUSIONS

This pilot study demonstrates a limited concordance between MammaPrint and EndoPredict. Differences in results could be explained by the inclusion of different gene sets in each platform, the use of different methodology, and the inclusion of clinicopathological parameters, such as tumor size and nodal status, in the EndoPredict test.

Prognostic Value of BRAF, PI3K, PTEN, EGFR Copy Number, Amphiregulin and Epiregulin Status in Patients with KRAS Codon 12 Wild-Type Metastatic Colorectal Cancer Receiving First-Line Chemotherapy with Anti-EGFR Therapy

INTRODUCTION

Mutational analysis of RAS is required for anti-epidermal growth factor receptor (EGFR) treatment for patients with metastatic colorectal cancer (mCRC). However, most patients with KRAS wild-type tumors still do not respond. Other molecules downstream of the EGFR may also play a role in resistance to EGFR therapies.

OBJECTIVE

Our objective was to investigate the clinical importance of biomarkers in relation to response, progression-free survival, and overall survival in patients with mCRC receiving first-line treatment with anti-EGFR therapy plus chemotherapy.

METHODS

We studied the EGFR pathway [EGFR, NRAS, BRAF, PIK3CA, phosphatase and tensin homolog (PTEN), amphiregulin (AREG), and epiregulin (EREG)] in 105 patients with mCRC KRAS codon 12 wild type. We analysed objective response, progression-free survival, and overall survival in molecularly defined subgroups of the patients receiving anti-EGFR therapy plus chemotherapy as first-line treatment.

RESULTS

We found a significant association between RAS wild-type, BRAF wild-type, EREG, and AREG overexpression and response to anti-EGFR therapy (p = 0.003, p = 0.015, p = 0.05, and p = 0.009, respectively). Progression-free survival and overall survival were lower in patients with RAS (p = 0.36 and p ≤ 0.001, respectively) or BRAF (p = 0.003 and p = 0.002, respectively) mutant tumors. Patients with EREG and AREG messenger RNA (mRNA) expression had longer survival than those with low-expression tumors; progression-free survival and overall survival were significant for AREG (p = 0.001 and p = 0.05, respectively). Patients with EGFR amplification tumors responded better to treatment and had better survival rates, although this was not significant. PIK3CA and PTEN were not associated with either response or survival. The multivariate logistic regression model for response showed only BRAF as a significant predictor after adjustment for the other covariates (p = 0.04, odds ratio 8.3, 95 % confidence interval 0.81-86.0).

CONCLUSIONS

RAS, BRAF, AREG, and EREG predict for efficacy of first-line anti-EGFR therapy in patients with mCRC.

Is regorafenib providing clinically meaningful benefits to pretreated patients with metastatic colorectal cancer?

Treatment with regorafenib has demonstrated statistically significant improvements in terms of overall survival, progression-free survival and disease control when compared with placebo in pretreated patients with metastatic colorectal cancer in two placebo-controlled, randomized, phase III trials (CORRECT and CONCUR). Similar results were observed in two open-label, single-arm studies (REBECCA and CONSIGN) performed in the real-world setting. But several authors have suggested that the benefit provided by regorafenib may not be clinically meaningful for these patients. Moreover, it has been suggested that not all subgroups of patients might benefit from regorafenib. The intention of this review is to provide an overview of the existing evidence for regorafenib in terms of efficacy, tolerability and quality of life in different subpopulations according to clinical and biological characteristics. Additionally, the magnitude of the clinical benefit provided by regorafenib to these patients has been explored and whether there are poorer outcomes in certain subpopulations.

Abstract 4838: Inhibitor of differentiation-1 (Id1) expression correlates with epithelial-mesenchymal transition (EMT)-related proteins in epithelial ovarian cancer (EOC) and constitutes a novel prognostic factor

Aim

The first aim of this work was to investigate the expression of inhibitors of differentiation (ID) proteins in advanced Epithelial Ovarian Cancer (EOC) and its relation with Epithelial to Mesenchymal (EMT)-related markers. Secondly, we also studied their relation with patient clinical and pathological characteristics in order to establish their role as prognostic factors.

Methods

ID proteins expression was analyzed in 59 samples from EOC patients. We performed inmunohistochemistry (IHC) on tissue microarray sections with specific antibodies for ID1, ID2, ID3 and ID4. Immunoreactivity was H-scored for intensity (range 0 to 3) multiplied by percentage of positive cells. It has been previously described that ID genes are involved in EMT, so we correlated IDs with EMT- regulators, including ECAD, ZEB1, ZEB2, SNAIL, SLUG, LOX and LOXL2. We also explored their relation with clinical variables in our cohort.

Results

ID2 and ID3 proteins are uniformly expressed in our EOC series. ID1 and ID2 are also overexpressed in different proportions (41% and 88% of cases respectively). No correlation between increased ID proteins expression and histological subtype, tumor grading, debulking surgery status or treatment response was detected. We have found that ID1 overexpression correlates with prognosis, for Overall Survival (OS), HR: 1.05 (95% CI: 1.02 - 1.07) in the univariate analysis and for Time to Treatment Failure (TTF) in both, uni- and multivariate analysis adjusted to clinical factors (HR: 1.06; 95%CI: 1.02 - 1.1). This finding was confirmed when specifically analyzing the worst prognosis group of patients with high grade serous malignancies. ID1 is known to be associated with more invasive features of cancer and with the EMT. In our cohort, its expression is correlated with some EMT-regulators, as ECAD and SLUG (p < 0,005).

Conclusions

ID proteins expression is frequently deregulated in EOC patients and it seems to influence clinical prognosis, mainly, ID1. Their usefulness as prognostic biomarkers should be further investigated in larger series.

Citation Format: Victoria Heredia, Andres Redondo, Jorge Barriuso, Alberto Berjón, Cristian Perna, Patricia Cruz, Alicia Hernández, Javier de Santiago, Esther Díaz, María Miguel, Beatriz Castelo, Laura Yébenes, Jaime Feliú, David Hardisson, Marta Mendiola. Inhibitor of differentiation-1 (Id1) expression correlates with epithelial-mesenchymal transition (EMT)-related proteins in epithelial ovarian cancer (EOC) and constitutes a novel prognostic factor. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4838. doi:10.1158/1538-7445.AM2015-4838

Clinical management of regorafenib in the treatment of patients with advanced colorectal cancer

Colorectal cancer is one of the most common tumors worldwide and at least 50 % of patients with this disease develop metastases. In this setting, additional treatment options are needed for patients presenting disease progression after exhausting all standard therapies. Regorafenib is an orally administered multikinase inhibitor which has been shown to provide survival benefits to patients with metastatic colorectal cancer (mCRC). Although most adverse events (AEs) associated with regorafenib may resolve within the first 8 weeks of treatment, some of them may require dose reduction or treatment interruption. Overall, while remaining aware of the safety profile of regorafenib and how to manage the most common toxicities related to its use, this drug should be considered a new standard of care for patients with pretreated mCRC. This review addresses practical aspects of its use, such as dosing, patient monitoring, and management of the most common regorafenib-related AEs.

Concordance of K-Ras status between colorectal cancer (CRC) primaries and related metastatic samples considering clinicopathological features

4053

Background: K-Ras mutations in CRC primaries may predict resistance to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies, but we don´t know its behaviour in metastatic tissue. The aims of this study were: 1) Evaluate the grade of concordance of K-Ras status between primary and related metastatic samples 2) Establish a correlation between k-ras status and individual clinicopathological features Methods: K-ras mutations were retrospectively analysed in primary tumours of 124 patients and 138 related metastatic sites. The primary tumour site was colon in 87 patients and rectum in 37. Sites of metastases were liver (115 samples,83.3%) and lung (23 samples,16.7%). Some patients underwent surgery several times. We analyzed K-Ras point mutations in codons 12 and 13 by direct DNA sequencing from paraffin-embedded tumour and studied its relation with 13 clinicopathological features Results: K-Ras mutation was observed in 42(33.6%) primary tumours and in 52(39.1%) related metastatic sites, being the grade of concordance between primary and metastatic sites of 93% (95% CI: 97.5–88.3%). Discordance was observed in 9 (7%) patients: in 2, K-Ras status was wild type in metastatic site and expressed a mutational pattern in the primary tumour; vice versa, in 7, the mutation status was detected in the metastases meanwhile primary tumour was wild type. We also found statistically significative differences in mutation patterns regarding the site of the metastasic tissue: K-ras mutations were detected in 13 lung samples (61.9%) and in 39 liver samples (34.8%) (p=0.028). Of all the clinicopathological features analyzed we confirmed an increase of mutated K-ras status in tumours which had presented as perforation (p=0.044). No other relation with clinicopathological data was detected Conclusions: With this observational analysis, we confirm the high concordance (superior to 90%) between primary and related metastatic sites in terms of K-Ras status; for the first time, we have reported a higher mutational pattern in lung metastases than in liver disease, founds that may have important relevance regarding clinical/treatment decisions. For the realization of this study we received a grant from Amgen.

No significant financial relationships to disclose.

[Rhino-cerebral mucormycosis and hematological neoplasia]

Mucormycosis is a rare infection that occurs in immunocompromised patients. The rhinocerebral form presents in diabetics as a severe necrotizing sinusitis and is not frequent in patients with haematologic malignancies. Diagnosis requires direct examination and culture of biopsy specimens. Two patients with rhinocerebral mucormycosis and haematologic neoplasms (Non-Hodgkin's lymphoma and acute myeloblastic leukaemia) are described. Both patients had severe drug-induced neutropenia when the infection appeared. One patient died in spite of aggressive treatment with surgery and amphotericin.

[Usefulness of sialic acid as a tumor marker]

In order to analyze the utility of sialic acid as a tumor mass marker, its levels have been determined in 253 neoplastic patients, 57 patients with non-tumoral pathology and 60 healthy controls. Significant differences in the sialic acid values were observed between the control group and the rest (p less than 0.001). When the neoplastic patients were studied according to the extension of their disease, we found that the SA levels in patients under complete remission were significantly lower than in the other stages (p less than 0.01) and that patients in stage IV presented the highest levels (p less than 0.05). Differences between stages I, II and III were not detected. Furthermore, no differences were observed regarding either the type of neoplasia or if the patients had or did not have tumor pathology. We conclude that sialic acid is a tumor marker with poor specificity that grossly relates with the tumor size.

[Meningeal carcinomatosis as the primary manifestation of breast cancer in a man]

Meningeal Carcinomatosis (MC) is a severe and usually late complication in the progressive development of some--5%--solid extraneural tumors. Breast and Lung adenocarcinomas are the two primary sites more often associated with this condition today. We present a case of male patient in whom MC was the initial and diagnostic manifestation of breast cancer. Autopsy study revealed a concomitant presence of a lung bronchoalveolar carcinoma. However, the cytopathology of Cerebrospinal Fluid and pathologic findings in leptomeninges showed a breast adenocarcinoma as primary site.