Cylindroma of the breast with CYLD gene mutation: a case report and review of the literature

BACKGROUND

Cylindroma of the breast is a rare benign neoplasm. Since its first description in 2001, 20 cases have been reported in the literature.

METHODS AND RESULTS

We report another case of this rare tumor in a 60-year-old woman with demonstration of the underlying molecular alteration. Histologically, the tumor showed the typical "jigsaw" pattern of a dual population of cells with a triple-negative phenotype. The pathognomonic mutation of the CYLD gene mutation was detected by whole exome sequencing. Cylindromas show morphological overlap with the solid-basaloid variant of adenoid cystic carcinoma, which renders this differential diagnosis difficult. However, distinction of these two lesions is of outmost importance, since cylindromas, in contrast to solid-basaloid variant of adenoid cystic carcinoma, behave in an entirely benign fashion.

CONCLUSIONS

Careful evaluation of morphological features such as mitotic figures and cellular atypia is crucial in the diagnostic work-up of triple-negative breast lesions. It is important to keep cylindroma in mind as a pitfall and possible differential diagnosis for the solid-basaloid variant of adenoid cystic carcinoma. Molecular detection of CYLD gene mutation is helpful in cases with ambiguous histology. With this case report, we aim to contribute to a better understanding of mammary cylindroma and facilitate the diagnosis of this rare entity.

Abstract 3984: GATA3 and MDM2 are synthetic lethal in estrogen receptor-positive breast cancers

Introduction: GATA3 is critical for the development of the mammary gland and the loss of its expression alters the estrogen receptor (ER) transcriptional program. Approximately 70%-80% of all breast cancers are ER-positive and 15-18% of them harbor GATA3 somatic mutations. Clinically, GATA3 loss defines a subset of patients with poor response to hormonal therapy and poor prognosis. As a transcription factor, however, GATA3 is not pharmacologically targetable. Synthetic lethality refers to the interaction between genetic events in two genes whereby the inactivation of either gene results in a viable phenotype, while their combined inactivation is lethal. This approach enables the indirect targeting of undruggable genes by disrupting their genetic interactors. In this study we sought to define Synthetic lethal partners for GATA3 and explore possible therapeutic targets

Methods: Putative synthetic lethal partners for GATA3 were identified using the recently developed SLIdR (Synthetic Lethal Identification in R) algorithm. The synthetic lethal interaction and the anti-tumoral effect of putative partner was evaluated via genetic silencing or pharmacological inhibition using in-vitro, ex-vivo and in-vivo models. Putative mechanisms of action were investigate using RNA sequencing and confirmed using molecular biology technologies.

Results: We identify MDM2 as synthetically lethal partner of GATA3 in ER-positive breast cancer. Using a siRNA approach, we first validated in-silico data by confirming that silencing MDM2 significantly reduces cell proliferation of GATA3-mutant in-vitro models by inducing apoptosis. Pharmacological inhibition of MDM2 using three different compounds (RG7388-idasanutlin, RAIN-32 and MI-733) significantly impaired tumor growth in GATA3-deficient models in vitro, in vivo and in patient-derived organoid/xenograft (PDO/PDX) harboring GATA3 somatic mutation. Additionally, we showed that the synthetic lethality between GATA3 and MDM2 is p53-dependent and acts at least partially via the PI3K/Akt/mTOR pathway. This suggests that GATA3 loss-of-function (via genetic alterations or other mechanisms) activates the PI3K/Akt/mTOR pathway and leads to resistance to apoptosis.

Conclusion: Our results present MDM2 as a novel therapeutic target in the substantial cohort of ER-positive, GATA3-mutant breast cancer patients. With MDM2 inhibitors widely available, our findings can be rapidly translated into clinical trials to evaluate in-patient efficacy.

Citation Format: Mattia Marinucci, Gaia Bianco, Mairene Coto-Llierena, John Gallon, Venkatesh Kancherla, Federica Panebianco, Stephanie Taha-Mehlitz, Sumana Srivatsa, Niko Beerenwinkel, Hesam Montazeri, Vijaya Tirunagaru, Marta De Menna, Caner Ercan, Ahmed Dahmani, Elodie Montaudon, Marianna Kruithof-de Julio, Luigi M. Terracciano, Rinath M. Jeselsohn, Robert C. Doebele, François-Clément Bidard, Elisabetta Marangoni, Charlotte K. Y. Ng, Salvatore Piscuoglio. GATA3 and MDM2 are synthetic lethal in estrogen receptor-positive breast cancers [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 3984.

Genomic analysis of focal nodular hyperplasia with associated hepatocellular carcinoma unveils its malignant potential: a case report

Background

Focal nodular hyperplasia (FNH) is typically considered a benign tumor of the liver without malignant potential. The co-occurrence of FNH and hepatocellular carcinoma (HCC) has been reported in rare cases. In this study we sought to investigate the clonal relationship between these lesions in a patient with FNH-HCC co-occurrence.

Methods

A 74-year-old female patient underwent liver tumor resection. The resected nodule was subjected to histologic analyses using hematoxylin and eosin stain and immunohistochemistry. DNA extracted from microdissected FNH and HCC regions was subjected to whole exome sequencing. Clonality analysis were performed using PyClone.

Results

Histologic analysis reveals that the nodule consists of an FNH and two adjoining HCC components with distinct histopathological features. Immunophenotypic characterization and genomic analyses suggest that the FNH is clonally related to the HCC components, and is composed of multiple clones at diagnosis, that are likely to have progressed to HCC through clonal selection and/or the acquisition of additional genetic events.

Conclusion

To the best of our knowledge, our work is the first study showing a clonal relationship between FNH and HCC. We show that FNH may possess the capability to undergo malignant transformation and to progress to HCC in very rare cases.

Standardizing Patient-Derived Organoid Generation Workflow to Avoid Microbial Contamination From Colorectal Cancer Tissues

The use of patient-derived organoids (PDO) as a valuable alternative to in vivo models significantly increased over the last years in cancer research. The ability of PDOs to genetically resemble tumor heterogeneity makes them a powerful tool for personalized drug screening. Despite the extensive optimization of protocols for the generation of PDOs from colorectal tissue, there is still a lack of standardization of tissue handling prior to processing, leading to microbial contamination of the organoid culture. Here, using a cohort of 16 patients diagnosed with colorectal carcinoma (CRC), we aimed to test the efficacy of phosphate-buffered saline (PBS), penicillin/streptomycin (P/S), and Primocin, alone or in combination, in preventing organoid cultures contamination when used in washing steps prior to tissue processing. Each CRC tissue was divided into 5 tissue pieces, and treated with each different washing solution, or none. After the washing steps, all samples were processed for organoid generation following the same standard protocol. We detected contamination in 62.5% of the non-washed samples, while the use of PBS or P/S-containing PBS reduced the contamination rate to 50% and 25%, respectively. Notably, none of the organoid cultures washed with PBS/Primocin-containing solution were contaminated. Interestingly, addition of P/S to the washing solution reduced the percentage of living cells compared to Primocin. Taken together, our results demonstrate that, prior to tissue processing, adding Primocin to the tissue washing solution is able to eliminate the risk of microbial contamination in PDO cultures, and that the use of P/S negatively impacts organoids growth. We believe that our easy-to-apply protocol might help increase the success rate of organoid generation from CRC patients.

The imprinted Zdbf2 gene finely tunes control of feeding and growth in neonates

Genomic imprinting refers to the mono-allelic and parent-specific expression of a subset of genes. While long recognized for their role in embryonic development, imprinted genes have recently emerged as important modulators of postnatal physiology, notably through hypothalamus-driven functions. Here, using mouse models of loss, gain and parental inversion of expression, we report that the paternally expressed Zdbf2 gene controls neonatal growth in mice, in a dose-sensitive but parent-of-origin-independent manner. We further found that Zdbf2-KO neonates failed to fully activate hypothalamic circuits that stimulate appetite, and suffered milk deprivation and diminished circulating Insulin Growth Factor 1 (IGF-1). Consequently, only half of Zdbf2-KO pups survived the first days after birth and those surviving were smaller. This study demonstrates that precise imprinted gene dosage is essential for vital physiological functions at the transition from intra- to extra-uterine life, here the adaptation to oral feeding and optimized body weight gain.

Gene expression profiling of human ovarian tumours

There is currently a lack of reliable diagnostic and prognostic markers for ovarian cancer. We established gene expression profiles for 120 human ovarian tumours to identify determinants of histologic subtype, grade and degree of malignancy. Unsupervised cluster analysis of the most variable set of expression data resulted in three major tumour groups. One consisted predominantly of benign tumours, one contained mostly malignant tumours, and one was comprised of a mixture of borderline and malignant tumours. Using two supervised approaches, we identified a set of genes that distinguished the benign, borderline and malignant phenotypes. These algorithms were unable to establish profiles for histologic subtype or grade. To validate these findings, the expression of 21 candidate genes selected from these analyses was measured by quantitative RT–PCR using an independent set of tumour samples. Hierarchical clustering of these data resulted in two major groups, one benign and one malignant, with the borderline tumours interspersed between the two groups. These results indicate that borderline ovarian tumours may be classified as either benign or malignant, and that this classifier could be useful for predicting the clinical course of borderline tumours. Immunohistochemical analysis also demonstrated increased expression of CD24 antigen in malignant versus benign tumour tissue. The data that we have generated will contribute to a growing body of expression data that more accurately define the biologic and clinical characteristics of ovarian cancers.

[Parasite identification in the surveillance of imported leishmaniasis cases in Italy]

An accurate Leishmania classification was defined since 1980s by the use of isoenzyme analysis. To date, this procedure still represents the reference identification technique, despite the increasing use of molecular approaches. Studies and surveillance methods on leishmaniases are strongly conditioned by the knowledge and mapping of all the parameters characterizing each nosogeographical entity. On this respect, the identification of parasites from all the actors of the natural life cycle plays a key role. With the increasing population movements and climate changes, novel risk factors could be identified associated to Leishmania geographical distribution and spreading: a) the introduction into Italy of new populations of L. infantum from other countries; b) the introduction of new Leishmania species that may find a suitable milieau to support their life cycle in our country. The objective of this report is to present the surveillance activity on imported leishmaniases by the Leishmania Identification Reference Centre, ISS. Two different methodologies were routinely applied: a) isoenzyme electrophoretic analysis, which requires parasite culture, and b) a number of molecular techniques, used for both diagnosis and parasite identification, differently applied according to the geographical origin of the suspected leishmaniasis case. When possible, both types of methodologies were applied. From 1986 to June 2002, 38 imported cases of leishmaniases were identified: 9 visceral (VL) and 29 cutaneous (CL) cases, of which 22 from the Old and 7 from the New World. Pathology, Leishmania species/zymodeme and geographical origin features are reported in the paper. Seven out of 9 VL patients were HIV positive, of whom 5 detected in the period 1993-1995. This high importation rate can be associated to the general increase in Mediterranean Leishmania/HIV coinfections in that period. Following HAART treatment, VL imported cases became occasional; no introduction of new L. infantum populations has been detected. On the other hand, our findings show an increase of CL imported cases from different areas of the Old and New Worlds. This phenomenon, however, is so far limited to new Leishmania species that could hardly be introduced in our country, because of their strict biological requirements (i.e. vectors and/or natural reservoir hosts). Since June 2002, 10 further suspected imported cases were recorded. For these patients--whose Leishmania identification is still in course--the origin/visited geographical areas were only slight different from the previous. However, the characteristics of the patients are changing: there are more immigrants that occasionally visited their place of origin, and Italian military staff.

Identification of the sibling species of the Anopheles maculipennis complex by heteroduplex analysis

The group of anopheline mosquitoes referred to as 'Anopheles maculipennis complex' includes the most important malaria vectors of the Palearctic Western region. The species belonging to this complex, however, are difficult or impossible to distinguish by morphological characters. To differentiate sibling palearctic species belonging to this complex, interspecific differences in the ITS2 sequences were used to set up a rapid and sensitive diagnostic tool based on heteroduplex analysis. The relative heteroduplex mobility allowed the following seven species to be readily distinguished: An. atroparvus, An. labranchiae, An. maculipennis s.s. , An. martinius, An melanoon, An. messeae and An. sacharovi.

Phylogenetic analysis of Phlebotomus species belonging to the subgenus Larroussius (Diptera, psychodidae) by ITS2 rDNA sequences

In the genealogy of Phlebotomus (Diptera: Psychodidae), morphological analyses have indicated that the subgenus Larroussius is a monophyletic group which is most closely related to the subgenera Transphlebotomus and Adlerius. We conducted a phylogenetic analysis of the relationships among six representative species of the subgenus Larroussius and one species representatitive of the Phlebotomus subgenus, assessing sequences of the Second Internal Transcribed Spacer (ITS2) of the ribosomal RNA (rRNA). Three of the species (P. perniciosus, P. ariasi and P. perfiliewi perfiliewi) were collected in different parts of the Mediterranean area. The trees estimated from parsimony and neighbour-joining analyses supported the monophyly of the Larroussius subgenus inferred from the morphological analysis. According to our data, P. ariasi may be a sister group to the rest of the Larroussius subgenus, although additional sequence data are needed to confirm this observation. Our results suggest that P. perniciosus and P. longicuspis are distinct species, in spite of the fact that there are only slight morphological differences. The strict congruence between the phylogeny of the Larroussius subgenus inferred from the ITS2 sequences and that based on morphological studies further confirmed the ability of the spacer sequence to identify recently-derived affiliations.

Phylogenetic relationships of seven palearctic members of the maculipennis complex inferred from ITS2 sequence analysis

The sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) were determined from seven palearctic mosquitoes species belonging to the Anopheles maculipennis species complex, namely An. atroparvus, An. labranchiae, An. maculipennis, An. messeae, An. melanoon, An. sacharovi and An. martinius. The length of the ITS2 ranged from 280 to 300 bp, with a GC content of 49.4-54.1%. With the exception of An. messeae, negligible levels of intraspecific polymorphism and no intrapopulation variation were observed. The phylogenetic relationships among the members of the maculipennis complex were inferred by maximum-parsimony analysis of the PAUP program and the neighbour-joining and maximum-likelihood analysis of the PHYLIP program. All of the trees obtained were almost identical in topology, although the relationships among three species, i.e. An. maculipennis, An. messeae and An. melanoon, remained unresolved. The phylogenies were in good agreement with the previous gene-enzyme and polytene chromosome banding pattern studies.

[Resistance to organophosphate insecticides in Culex pipiens L. (Diptera: Culicidae) and first signal of the presence of A5-B5 esterase in Italy]

After a short review on insecticide resistance in mosquitoes, the results of a study on organophosphate (OP) resistance, carried out on 2 Culex pipiens L. field populations from North-eastern Italy, are reported. The A1 an A4-B4 or A5-B5 esterases were detected in our sample by starch gel electrophoresis. In order to differentiate between A4-B4 and A5-B5 esterases, restriction fragment length polymorphism (RFLP) analysis at the esterases B locus was performed: both A4-B4 and A5-B5 aplotipes were found in one of the studied populations. This is the first record of A5-B5 esterases in continental Europe.

Esterases A5-B5 in organophosphate-resistant Culex pipiens from Italy

Culex pipiens mosquitos from Lignano city, Udine province, northeast Italy, were found to carry over-produced non-specific esterases A1, A2-B2 and A4-B4 or A5-B5, detected by starch gel electrophoresis, giving multiple resistance to organophosphorus insecticides. In order to differentiate between A4-B4 and A5-B5 esterases, the latter known only from Cyprus whereas the former is widespread in Italy and elsewhere, restriction fragment length polymorphism (RFLP) analysis was performed at the esterase B locus. Both B4 and B5 haplotypes were found. This is the first record of A5-B5 esterase-mediated resistance in continental Europe.

Sequence and secondary structure of the rDNA second internal transcribed spacer in the sibling species Culex pipiens L. and Cx. quinquefasciatus Say (Diptera: Culicidae)

The primary and secondary structure of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) of two members of the Cx. pipiens complex, Cx. pipiens and Cx, quinquefasciatus, were examined in order to better understand the relationships between these two sibling mosquito species. The length of the sequenced rDNA fragments was 512 bp (Cx. pipiens) and 513 bp (Cx. quinquefasciatus), including the ITS2 regions and flanking 5.8S-28S coding regions. The ITS2 sequences of Cx. pipiens and Cx. quinquefasciatus were 297 and 298 bp in length respectively and showed a 97% identity. In fact, they had identical G+C content (58%) and the only differences observed are six mismatches (three transitions/three transversions), six single-base and one triple-base deletions/ insertions. The observed ITS2 secondary structures of Cx. pipiens and Cx. quinquefasciatus were very similar. Furthermore, the ITS2 sequences of specimens belonging to three populations of Cx. pipiens from Italy and four populations of Cx. quinquefasciatus (three from Africa and one from North America) were analysed in order to detect the presence of potential species-specific diagnostic restriction sites.

Insecticide resistance genes in Culex pipiens (Diptera: Culicidae) from Italy: esterase B locus at the DNA level

Restriction fragment length polymorphism (RFLP) analysis at the esterase B locus was performed in samples from four populations of Italian Culex pipiens pipiens L. to identify correctly, at the molecular level, the resistance gene. The absence of the amplified B2 haplotype was confirmed, indicating that it has not increased in frequency after its detection in continental Italy around 1985. The B4 haplotype was detected in all populations at the same frequencies as a previous starch gel survey. The possibility that B4 amplification has occurred only once and has migrated across western Mediterranean region is supported by the data. A1 also was detected indirectly by the presence of its closely linked B allele. The B5 haplotype apparently was absent. No amplification at the esterase B locus was detected, except B4, indicating a low rate of occurrence of new amplification at this locus.

Mechanisms of insecticide resistance in field populations of Culex pipiens from Italy

Results of a study on organophosphate (OP) resistance carried out on 4 Italian field populations of Culex pipiens are reported. The A1, A4-B4 and/or A5-B5 nonspecific esterases and insensitive acetylcholinesterase (AChE) were detected in our samples. A2-B2 esterases previously recorded in Italy were not observed. The A4-B4 and/or A5-B5 esterases were first found in Italy where they are at present widespread. Both nonspecific esterases and insensitive AChE are involved in OP resistance, although the high level of OP resistance observed in the Padova population could be correlated with both a high frequency of insensitive AChE and A5-B5 esterases.

Human embryonic hemopoiesis. Kinetics of progenitors and precursors underlying the yolk sac----liver transition

Human embryonic development involves transition from yolk sac (YS) to liver (L) hemopoiesis. We report the identification of pluripotent, erythroid, and granulo-macrophage progenitors in YS, L, and blood from human embryos. Furthermore, comprehensive studies are presented on the number of hemopoietic progenitors and precursors, as well as of other cell types, in YS, L, and blood at precisely sequential stages in embryos and early fetuses (i.e., at 4.5-8 wk and 9-10 wk postconception, respectively). Our results provide circumstantial support to a monoclonal hypothesis for human embryonic hemopoiesis, based on migration of stem and early progenitor cells from a generation site (YS) to a colonization site (L) via circulating blood. The YS----L transition is associated with development of the differentiation program in proliferating stem cells: their erythroid progeny shows, therefore, parallel switches of multiple parameters, e.g., morphology (megaloblasts----macrocytes) and globin expression (zeta----alpha, epsilon----gamma).

Expression of cellular oncogenes in primary cells from human acute leukemias

The structure and the expression of 11 cellular oncogenes (protooncogenes) were analyzed in primary cells from 20 acute lymphocytic (ALL) and 31 acute myelogenous (AML) leukemia patients. Neoplastic cells, obtained prior to initiation of therapy, were purified and classified, on the basis of both surface antigen pattern and morphology, into pre-B, B, and T ALL and M1-M5 AML. RNA was extracted and analyzed for expression of cellular oncogenes coding for nuclear proteins (c-myc, c-myb, c-fos), the beta-chain of platelet-derived growth factor (c-sis), growth factor receptors or related proteins (c-src, c-abl, c-fes, c-erbB), or putative intermediate transducers of mitogenic signals (c-Ha-ras, c-Ki-ras, c-N-ras). Quantitative analysis of total RNA was carried out by dot blot hybridization to specific cDNA or genomic probes. Number and size of transcripts were evaluated by blot hybridization of electrophoretically fractionated poly(A)+ RNA. Expression of c-myc and c-myb was detected in all leukemic cells at variable levels and was characterized by well-defined patterns within ALL subtypes. Conversely, significant levels of c-fos transcripts were detected only in myelomonocytic (M4) and monocytic (M5) leukemias. Among the "src-family," c-fes was expressed more in AML than ALL, and c-abl was expressed at variable but not elevated levels in all leukemia types. c-Ha-ras was uniformly expressed at low levels, as in non-neoplastic cells. c-Ki-ras transcription was detected only in T ALL; N-ras expression was barely demonstrable. The structure of these protooncogenes was not grossly modified, as evaluated by Southern analysis, except for c-myc rearrangement in B ALL. These studies indicate that cellular oncogene expression in specific subtypes of leukemic cells may relate to either the proliferative activity (c-myc, c-myb) or the differentiation state (c-fos) of the cells, or possibly to expression of receptors for putative hemopoiesis-related growth factors (c-fes, c-abl). Our data provide a basis for in-depth analysis of protooncogene expression in normal and neoplastic hemopoiesis.

Haemoglobin switching in human embryos: asynchrony of zeta----alpha and epsilon----gamma-globin switches in primitive and definite erythropoietic lineage

Haemoglobin switching in humans provides a unique model for investigating the mechanisms underlying expression of a developmentally regulated gene family. Numerous studies have focused on the switch from fetal to adult (that is, gamma----beta) globin, but little is known about the embryonic----fetal (that is, zeta----alpha and epsilon----gamma) switches, as well as the transition from 'primitive' yolk sac to 'definitive' liver erythropoiesis. Here we have studied the embryonic----fetal haemoglobin switches in yolk sac, liver and circulating blood erythroblasts from 25 embryos and 6 fetuses. Globin synthesis was also evaluated in purified 'primitive' and 'definitive' erythroblasts. Primitive erythroblasts synthesize essentially zeta and epsilon chains at 5 weeks and alpha- and epsilon-globin with a minor aliquot of zeta and gamma chains at 6-7 weeks, whereas definitive erythroblasts produce alpha and epsilon + gamma + beta-globin at 6 weeks but only alpha and gamma + beta chains from 8 weeks onward. In both lineages the zeta----alpha and the epsilon----gamma switches are asynchronous, the former preceding the latter. Furthermore, zeta- and beta-globin synthesis is restricted to primitive and definitive erythroblasts respectively. These findings are discussed in terms of a monoclonal model for haemoglobin switching in early human ontogeny.

Association of heterocellular HPFH, beta(+)-thalassaemia, and delta beta(0)-thalassaemia: haematological and molecular aspects

An Italian family in which heterocellular hereditary persistence of fetal haemoglobin (HPFH) interacts with both beta(+)- and delta beta-thalassaemia is described. The index case was an 8 year old girl who was presumed to inherit both heterocellular HPFH and beta (+)-thalassaemia from her mother and delta beta-thalassaemia from her father. She was healthy and never needed blood transfusions. The possible contribution of heterocellular HPFH to the less severe expression of the compound delta beta/beta(+)-thalassaemia heterozygosity is discussed. By DNA analysis the specific delta beta-thalassaemia defect on the gamma delta beta globin gene region has been established. In addition, a previously unreported association of a polymorphic restriction site haplotype with a beta (+)-thalassaemia mutation has been observed.

Delta beta-thalassaemia in southern Italy: evidence for a single mutational event

Haematological and molecular studies on 32 heterozygotes for G gamma A gamma delta beta(0)-thalassaemia from 15 unrelated families from southern Italy are reported. The haematological features of G gamma A gamma delta beta(0)-thalassaemia carriers are compared with those of beta-thalassaemia and Hb Lepore heterozygotes. Striking similarity exists between the phenotypic expression of beta-thalassaemia and Lepore mutations. Globin gene mapping studies indicated that the molecular lesion underlying delta beta-thalassaemia is a large deletion starting from the large intervening sequence of the delta gene and extending downstream from the beta gene. The possibility that delta beta-thalassaemia haplotypes in southern Italy originated from a single mutational event is discussed.

Heterocellular hereditary persistence of fetal hemoglobin (HPFH). Molecular mechanisms of abnormal gamma-gene expression in association with beta thalassemia and linkage relationship with the beta-globin gene cluster

We report a study of four families of Italian origin in which heterocellular HPFH is inherited linked to beta thalassemia over two or three generations. The HPFH + beta thalassemia carriers showed thalassemic blood pictures and elevated HbF and F-cell number without increase in the HbF/F-cell content. Association of this gene complex with a second beta thalassemia trait gives rise to a mild clinical picture characterized by 9-12 g/dl of mainly HbF in peripheral blood and no transfusion requirement. In two families, independent segregation of the HPFH or beta-thal trait was observed, and in one case the study of the DNA polymorphisms within the gamma delta beta gene cluster indicated that the HPFH mutation lies outside that DNA region. In one family the coexistence of a polymorphic variant of the A gamma chain (the A gamma T chain) allowed us to demonstrate that the increased gamma chain synthesis caused by the heterocellular HPFH determinant is directed by both chromosomes.

Molecular heterogeneity of beta thalassaemia in the Italian population

Fifty-one subjects originating from Southern Italy and affected by Cooley's anaemia have been studied in order to define the degree of heterogeneity of beta thalassaemia mutations in this high incidence area. Restriction endonuclease mapping has been carried out on genomic DNA by the Southern blot technique both to exclude the existence of gross deletions or rearrangements and to establish the relative frequency of four polymorphic restriction sites (i.e. G gamma and A gamma Hind III, beta Ava II and beta Bam HI) within the gamma delta beta gene region. In 28 subjects unequivocal linkage of the four polymorphic sites has been determined leading to the identification of seven different chromosome haplotypes, six of which had previously been reported associated with specific beta(0) and beta(+) thalassaemia mutations. Globin chain synthesis studies on peripheral blood reticulocytes indicated that subjects carrying the same genotype may behave differently as far as the beta chain production is concerned relative to both the alpha and the non-alpha chains. Thus, beta thalassaemia turns out to be quite heterogeneous even in this limited geographical area. Beta(+) mutations appear to be predominant, particularly those affecting nuclear precursor RNA splicing to mature beta globin mRNA.

Molecular mechanisms of human hemoglobin switching: selective undermethylation and expression of globin genes in embryonic, fetal, and adult erythroblasts

The globin chain synthetic pattern and the extent of DNA methylation within embryonic, fetal, and adult beta-like globin gene domains were evaluated in greater than or equal to 90% purified human erythroblasts from yolk sacs and fetal livers in the 6- to 12-wk gestational period as well as from adult marrows. The 6-wk erythroblasts produce essentially embryonic epsilon chains, whereas the 12-wk erythroblasts synthesize largely fetal gamma globin and the adult marrow erythroblasts synthesize almost exclusively adult beta chains. In all phases of ontogenic development, a strong correlation exists between DNA hypomethylation in the close flanking sequences of globin genes and their expression. These results suggest that modulation of the methylation pattern may represent a key mechanism for regulating expression of human globin genes during embryonic leads to fetal and fetal leads to adult Hb switches in humans. In ontogenic development this mechanism might in turn correlate with a gradual modification of chromatin structure in the non-alpha gene cluster, thus leading to a 5' leads to 3' activation of globin genes in a balanced fashion.

The delta beta crossover region in Lepore boston hemoglobinopathy is restricted to a 59 base pairs region around the 5' splice junction of the large globin gene intervening sequence

Genomic DNA from a hemoglobin (Hb) Lepore Boston (delta 87 Gln beta 116 His) homozygote of Southern Italian origin has been studied in order to map the fusion point between the delta and beta genes. An Ava II restriction endonuclease recognition sequence, located 12 base pairs (bp) downstream from the 5' end of the beta gene large intervening sequence, has been taken as marker of the beta-like portion of the fusion gene. This site was present even in the delta beta gene, allowing the localization of the crossover area to a 59-bp region extending from the first nucleotide of the Leu codon in position 88 to the 11th nucleotide of the large intervening sequence. The analysis of the DNA restriction polymorphisms in the gamma delta beta globin gene region provides evidence that a single mutational event originated the Lepore delta beta genes, at least in the Italian population.

Hemoglobin Maputo: a new beta-chain variant (alpha 2 beta 2 47 (CD6) Asp replaced by Tyr) in combination with hemoglobin S, identified by high performance liquid chromatography (HPLC)

During a routine hematological investigation, a slowly-moving hemoglobin variant was detected in a 2-year-old child from Maputo (Mozambique) in combination with hemoglobin S. Structural studies carried out by HPLC demonstrated a previously unreported amino acid substitution, beta 47 (CD6) Asp replaced by Tyr. The new hemoglobin variant has been named hemoglobin Maputo.

Hemoglobin bologna (alpha 2 beta 2 61 (E5) lys replaced by met). An abnormal human hemoglobin with low oxygen affinity

An abnormal human hemoglobin was found in association with beta-thalassemia in a hemolysate from an 11-year-old healthy child living in Bologna (northern Italy). Structural studies demonstrated a previously unreported amino acid substitution, beta 61 (E5) Lys replaced by Met (this is an external residue). The new variant has been named Hb Bologna, and is characterized by a reduced oxygen affinity. Family studies indicated that the variant had been inherited from the father, a 41-year-old male of Southern Italian origin. Also, a brother of the propositus was found to be an abnormal Hb carrier.

beta Thalassemia associated with increased HB F production. Evidence for the existence of a heterocellular hereditary persistence of fetal hemoglobin (HPFH) determinant linked to beta thalassemia in a southern Italian population

A family has been observed in which a beta thalassemia determinant is inherited over three generations together with high Hb F level (8-12%) and increased number of fetal-hemoglobin-containing-cells (F-cells). The values of red cell indices and globin chain synthesis ratios, yet typical of beta thalassemia, were significantly shifted to the normal values when compared with those of typical beta thalassemia heterozygotes belonging to the same family group. The occurrence in these individuals of a heterocellular hereditary persistence of fetal hemoglobin (HPFH) determinant and its linkage relationship with the beta thalassemia is discussed. In the third generation two adult individuals were beta thalassemia homozygotes having inherited a beta thalassemia determinant from one parent and a beta thalassemia together with the HPFH determinant from the other. They showed an extremely mild clinical condition, and 11-12 g/dl of mainly Hb F without having ever required blood transfusions. Virtually all the red cells were F-cells in both subjects. The importance of the coexistence of HPFH determinants capable of increasing the size of the F-cell population in patients affected by homozygous thalassemia is discussed, considering the sensible benefit which derives from enhanced Hb F production in this syndrome.

The biosynthesis of hemoglobin G San Josè (beta 7(A4) Glu replaced by Gly)

This report is concerned with the evaluation of hematological parameters and the percentage level of the abnormal hemoglobin (Hb) G San Josè as found in 4 heterozygous carriers from a family of Sicilian origin. Biosynthetic studies and in vitro recombination experiments strongly indicate that abnormal beta chains are synthesized at lower rate than beta A chains and exhibit a minor affinity (relative to beta A chains) for complementary chains in a condition of relative aA chain deficiency. The possibility that the low affinity of beta G chains for a chains may play a decisive role in controlling the level of the abnormal Hb in the peripheral blood of the present non-a-thalassemic abnormal Hb carriers is therefore discussed.

Post-translational control of human hemoglobin synthesis: the role of the differential affinity between globin chains in the control of mutated globin gene expression

The interactions between beta-thalassemia and the human hemoglobin (Hb) alpha-chain variants, Hb Hasharon, Hb O Idonesia and Hb J Paris, and between alpha-thalassemia and the beta-chain variants, Hb S, Hb C and Hb G San José, which are characterized by preferential decrease of the abnormal Hb level in peripheral bloods, have been studied. Both biosynthesis studies in reticulocytes and determination of the relative affinity of abnormal chains for normal complementary chains by in vivo recombination experiments, involving globin chains previously isolated in their native form, have been carried out in order to provide insights on the molecular events following the synthesis of the mutant chains under conditions of complementary chain deficiency. Furthermore, we have measured the relative affinity for complementary chain of beta D Los Angeles- and alpha J Rovigo-chains, the level of which does not decay in thalassemic carriers, and of alpha Legnano- and beta Osu Christiansborg-chains, which have not yet been observed in association with thalassemias. Our experiments indicated that the differential affinity for beta-chains is not always the major post-translational control mechanism which regulates the level of certain alpha-chain variants in beta-thalassemic heterozygotes, and that preferential removal of abnormal chains by proteolytic enzymes is likely to play an important role in most cases. On the other hand, the low affinity of certain variant beta-chains for alpha-chains may offer an explanation for the low level of certain beta-chain variants in peripheral blood of non-thalassemic carriers, as well as to their decrease under conditions of relative alpha-chain deficiency (alpha-thalassemias).

Possible duplication of the hemoglobin alpha chain locus in sheep

Only one type of alpha chain has been described so far in the hemoglobins of adult domestic sheep. A variant (Hb D) of the alpha chain, characterized by a substitution glycine leads to aspartic acid at position 15, has been described in Yugoslavian sheep. In this paper we report the identification of a second alpha chain (alpha 2), observed in several sheep when the globin was analyzed by CM-cellulose chromatography or the total hemolysate submitted to isoelectric focusing. The ratio of this chain to the usual one (alpha 1) in the globin of different animals is equal to either 1 : 2 or 1 : 4. The structural difference between alpha 1 and alpha 2 chains consists in the replacement of a leucine residue by an histidine in the position 113 or 114 of the polypeptide chain. Preliminary data on the frequency of the alpha 2 chain in eight domestic breeds indicate that this chain is fairly common, being present in 15 out of 40 animals examined. The results of breeding experiments between sheep of an appropriate alpha chain phenotype suggest the possibility of a duplication of the hemoglobin alpha locus in the Ovinae.

A new human hemoglobin variant: Hb BARI (alpha 2 45 (CD3) His leads to Gln beta 2)

An alpha-chain variant hemoglobin was found in the hemolysate of a 21-year-old healthy male living in Bari (Puglia, Italy). Structural studies demonstrated a previously unreported amino acid substitution, alpha 2 45 (CD3) His leads to Gln beta 2, involving a distal heme contact. The new variant has been named Hb Bari. Its electrophoretic behavior was the same as for Hb A; it was stable to both isopropanol and heat denaturation and exhibited normal functional properties, with respect to whole blood and stripped hemolysate studies. The level of Hb Bari was about 20% in the observed carrier. No relative was available for further investigations.