The importance of minimal residual disease for detection of late relapse in Bprecursor acute lymphoblastic leukemia.

BACKGROUND: The minimal residual disease (MRD) level in patients with B-precursor acute lymphoblastic leukemia (B-ALL) is the strongest independent predictor of relapse and survival. Assessment of MRD plays a crucial role in the treatment of B-ALL. CASE REPORT: We performed long-term monitoring of a 30-year-old woman with B-ALL of standard risk for MRD using multiparametric flow cytometry (MFC). After five years of monitoring, molecular relapse of the disease was confirmed. CONCLUSION: This case illustrates that more extended monitoring for MRD, even by only MFC when other newer sophisticated diagnostics are not available, is essential in detecting early relapse in patients with B-ALL of standard risk. HIPPOKRATIA 2022, 26 (1):38-40.

Proliferative characteristics of Philadelphia-negative myeloproliferative neoplasms - clinical implications.

INTRODUCTION: Philadelphia-negative myeloproliferative neoplasms (Ph- MPN) are characterized by overproduction of one or more blood cell lines. METHODS: We studied the proliferative characteristics of 91 patients with de novo Ph- MPN. Colony-forming cells (CFC) and endogenous colonies (EC), from bone marrow (BM) and/or peripheral blood (PB), were analyzed by colony assay based on methylcellulose. The level of circulating CD34+ cells was determined by flow cytometry. RESULTS: The total number of PB CFC in primary myelofibrosis (PMF) was increased compared to the control sample (P < 0.01) and essential thrombocythemia (ET) (P < 0.05). The highest number of BM and PB EC was observed in polycythemia vera (PV) (P < 0.01). Increased levels of CD34+ cells characterized early-prefibrotic (57%) and advanced-fibrotic PMF (90%) as compared to PV (34%) and ET (32%) (P < 0.01). In the whole Ph- MPN group, the total number of PB CFC (P < 0.01), PB EC (P < 0.05), and CD34+ cells (P < 0.01) correlated with the degree of BM fibrosis. Higher levels of circulating CD34+ cells in PMF correlated with the total number of PB EC (P < 0.05) and degree of BM fibrosis (P < 0.01). CONCLUSIONS: Exploration of the PB proliferative characteristics of Ph- MPN on diagnosis may be helpful in revealing early-prefibrotic PMF. Monitoring the levels of circulating CD34+ cells may provide a sensitive indicator of fibrotic evolution in PV and PMF.

Gene discovery in oral squamous cell carcinoma through the Head and Neck Cancer Genome Anatomy Project: confirmation by microarray analysis.

The near completion of the human genome project and the recent development of novel, highly sensitive high-throughput techniques have now afforded the unique opportunity to perform a comprehensive molecular characterization of normal, precancerous, and malignant cells, including those derived from squamous carcinomas of the head and neck (HNSCC). As part of these efforts, representative cDNA libraries from patient sets, comprising of normal and malignant squamous epithelium, were generated and contributed to the Head and Neck Cancer Genome Anatomy Project (HN-CGAP). Initial analysis of the sequence information indicated the existence of many novel genes in these libraries [Oral Oncol 36 (2000) 474]. In this study, we surveyed the available sequence information using bioinformatic tools and identified a number of known genes that were differentially expressed in normal and malignant epithelium. Furthermore, this effort resulted in the identification of 168 novel genes. Comparison of these clones to the human genome identified clusters in loci that were not previously recognized as being altered in HNSCC. To begin addressing which of these novel genes are frequently expressed in HNSCC, their DNA was used to construct an oral-cancer-specific microarray, which was used to hybridize alpha-(33)P dCTP labeled cDNA derived from five HNSCC patient sets. Initial assessment demonstrated 10 clones to be highly expressed (>2-fold) in the normal squamous epithelium, while 14 were highly represented in the malignant counterpart, in three of the five patient sets, thus suggesting that a subset of these newly discovered transcripts might be highly expressed in this tumor type. These efforts, together with other multi-institutional genomic and proteomic initiatives are expected to contribute to the complete understanding of the molecular pathogenesis of HNSCCs, thus helping to identify new markers for the early detection of preneoplastic lesions and novel targets for pharmacological intervention in this disease.

Proteomic profiling of the cancer microenvironment by antibody arrays.

Critical changes in protein expression that enable tumors to initiate and progress originate in the local tissue microenvironment, and there are increasing indications that these microenvironmental alterations in protein expression play critical roles in shaping and directing this process. As a model to better understand how patterns of protein expression shape the tissue microenvironment, we analyzed protein expression in tissue derived from squamous cell carcinoma of the oral cavity through an antibody microarray approach for high-throughput proteomic analysis. Utilizing laser capture microdissection to procure total protein from specific microscopic cellular populations, we demonstrate that quantitative, and potentially qualitative, differences in expression patterns of multiple proteins within epithelial cells reproducibly correlate with oral cavity tumor progression. Furthermore, differential expression of multiple proteins was also found in stromal cells surrounding and adjacent to regions of diseased epithelium that directly correlated with tumor progression of the epithelium. Most of the proteins identified in both cell types are involved in signal transduction pathways, thus we hypothesize that extensive molecular communication involving complex cellular signaling between epithelium and stroma play a key role in driving oral cavity cancer progression.

Activation of epiblast gene expression by the hypoblast layer in the prestreak chick embryo.

Axis formation is a highly regulated process in vertebrate embryos. In mammals, inductive interactions between an extra-embryonic layer, the visceral endoderm, and the embryonic layer before gastrulation are critical both for anterior neural patterning and normal primitive streak formation. The role(s) of the equivalent extra-embryonic endodermal layer in the chick, the hypoblast, is still less clear, and dramatic effects of hypoblast on embryonic gene expression have yet to be demonstrated. We present evidence that two genes later associated with the gastrula organizer (Gnot-1 and Gnot-2) are induced by hypoblast signals in prestreak embryos. The significance of this induction by hypoblast is discussed in terms of possible hypoblast functions and the regulation of axis formation in the early embryo. Several factors known to be expressed in hypoblast, and retinoic acid, synergistically induce Gnot-1 and Gnot-2 expression in blastoderm cell culture. The presence of retinoic acid in prestreak embryos has not yet been directly demonstrated, but exogenous retinoic acid appears to mimic the effects of hypoblast rotation on primitive streak extension, raising the possibility that retinoid signaling plays some role in the pregastrula embryo.

Differentiation potential of rat amnion.

The differentiation potential of rat amnion was investigated by explantation to different extrauterine sites and by culturing in vitro. Amnion differentiated into full skin by a process that is morphologically indistinguishable from normal skin development (interactions of the surface embryonic ectoderm and underlying mesenchyme). This process is not dependent on the age of the amnion but is dependent on the culture conditions used. Possible implications of these findings are discussed.

p185neu is expressed in yolk sac during rat postimplantation development.

We have shown that the neu oncogene product (p185neu) is not present in the rat embryo before organogenesis. However, coincident with the onset of organogenesis, p185neu was detected in neural and connective tissue as well as in the secretory epithelium as was described by Kokai et al. (1987). In addition, p185neu is also expressed in the rat visceral yolk sac (VYS) endodermal cells but not in the mesenchymal and mesothelial layers of the same structure nor in the amnion. The first detectable sign of p185neu expression in VYS was found at d 11 of gestation and the levels of protein increased towards the end of pregnancy. In the yolk sac carcinoma (YSC), which is considered to be the malignant counterpart of the rat yolk sac, p185neu was observed only within columnar epithelial cells (the visceral component of the neoplasm) while parietal endoderm-like cells were devoid of detectable protein. From d 9 of pregnancy up to delivery some of the trophoblastic giant cells also showed a faint to moderate immunoreactivity. Results are presented which would indicate a possible role of p185neu in rat embryogenesis.

Development of separated germ layers of rodent embryos on ectopic sites: a reappraisal.

The method of separation of germ layers of rodent embryos by treating the embryonic shields with proteolytic enzymes and by microsurgery with the subsequent transplantation to ectopic sites has helped to gain a more detailed insight into what is going on during gastrulation in mammals. The space under the kidney capsule of adult animals seems to be the most appropriate ectopic site for transplantation of early postimplantation rat embryos or separated germ layers. After transplantation the grafts develop into teratomas whose complex histological structure reflects the initial developmental capacities of the graft. At the pre-primitive streak and the early primitive streak stages the primitive ectoderm differentiates into tissue derivatives of all three definitive germ layers, often in complex organotypic combinations. This is indirect evidence that all cells of the embryonic body originate from the primitive embryonic ectoderm. Halves of the primitive ectoderm obtained by a longitudinal or transverse cut through the egg cylinder give the same result. At the head fold stage the capacity for differentiation of the ectoderm is restricted to ectodermal and mesodermal derivatives. One day before gastrulation the isolated primitive ectoderm is not able to differentiate as renal isograft. The mesoderm isolated at the head fold stage and at later stages when its segmentation occurs, differentiates almost exclusively into the brown adipose tissue. The embryonic endoderm differentiates only in combination with the mesoderm. After transplantation the embryonic ectoderm loses its epithelial organization and breaks up into a mass of mesenchyme-like cells in which epithelial structures subsequently appear and differentiate in a way reminiscent of the reaggregation of cells in mixed cell suspension in vitro.