66 Significance of Percutaneous Biopsy in the Clinical Management of Renal Masses

Aim

Percutaneous renal mass biopsy is increasingly used in the management of renal masses. The objective of our study was to determine the significance of percutaneous renal mass biopsy and its impact on clinical management.

Method

Retrospective study of all patients who had image guided percutaneous renal mass biopsy health-board wide from April 2011 to April 2019. Renal mass biopsies were performed for either a localised or metastatic renal mass. Results of the renal biopsies were compared to final diagnosis to determine diagnostic accuracy measured by sensitivity, specificity, negative predictive value and positive predictive value.

Results

Out of 429 patients who had a renal biopsy, 91 patients- 55 males (61%) and 36 females (39%) were included in the final analysis. The mean age of the study population was 66 years (range 46-87). Renal mass biopsies were performed using coaxial 18-gauge core needle technique. We categorised patients into two groups (metastatic renal masses and localised renal mass). Sixty-eight patients had biopsies for metastatic disease and 23 patients had biopsies for a localised renal mass. In the localised disease group, the sensitivity was 100%, positive predictive value was 82% (95% CI, 48.2-97.7%) and the negative predictive value was 100% (95% CI, 66.4-100%) (Clopper Pearson Method). For patients with metastatic renal mass the positive predictive value was 83%.

Conclusions

Percutaneous renal mass biopsy may have a role for metastatic renal cancers that require targeted therapy and localised masses that require curative treatment.

Association between multiple respiratory viral infections and pediatric intensive care unit admission among infants with bronchiolitis

Background

It is unclear whether multiple respiratory viral infections are associated with more severe bronchiolitis requiring pediatric intensive care unit (PICU) admission. We aimed to identify the association between multiple respiratory viral infections and PICU admission among infants with bronchiolitis.

Methods

We performed a 1:1 case-control study enrolling previously healthy full-term infants (≤12 months) with bronchiolitis admitted to the PICU as cases and those to the general pediatric ward as controls from 2015 to 2017. Multiplex polymerase chain reaction (PCR) was used for detection of the respiratory viruses. We summarized the characteristics of infants admitted to the PICU and the general pediatric unit. Multivariable logistic regression analysis was used to fit the association between multiple respiratory viral infections (≥2 strains) and PICU admission.

Results

A total of 135 infants admitted to the PICU were compared with 135 randomly selected control infants admitted to the general pediatric unit. The PICU patients were younger (median: 2.2 months, interquartile range: 1.3–4.2) than the general ward patients (median: 3.2 months, interquartile range: 1.6–6.4). Respiratory syncytial virus (74.1%), rhinovirus (28.9%), and coronavirus (5.9%) were the most common viruses for bronchiolitis requiring PICU admission. Patients with bronchiolitis admitted to the PICU tended to have multiple viral infections compared with patients on the general ward (23.0% vs. 10.4%, P < 0.001). In the multivariable logistic regression analysis, bronchiolitis with multiple viral infections was associated with higher odds of PICU admission (adjusted odds ratio: 2.56, 95% confidence interval: 1.17–5.57, P = 0.02).

Conclusion

Infants with multiviral bronchiolitis have higher odds of PICU admission compared with those with a single or nondetectable viral infection.

The genome of the social amoeba Dictyostelium discoideum

The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.

Fibrous tumors in children - a morphologic and interphase cytogenetic analysis of problematic cases

We describe and discuss the findings by fluorescent in situ hybridization (FISH) for detection of non-random chromosomal gains, in a group of unusual fibrous lesions in children. Nuclear disaggregation was used to prepare slides from eight cases which were hybridized using alpha-satellite enumeration probes for chromosomes 8, 11 and 17. Trisomy 8 and 11 were detected in a high percentage of nuclei in cases of congenital/infantile fibrosarcomas (ranging from 45 to 80%), and in a low grade fibrosarcoma in an older child (23%). Only gains of chromosome 17 were detected in a case of infantile fibromatosis (22%). In this study we have found that given the unconventional histopathologic features, the detection of more than one non-random chromosomal gains by FISH, may aid in further defining fibrous tumors in children, and may be useful as an ancillary diagnostic test in the future.

The clinical application of interphase FISH in prenatal diagnosis

Fluorescence in situ hybridization (FISH) for five chromosomes (13, 18, 21, X and Y) detected 87 of 107 (81%) of the chromosome aberrations identified by conventional chromosome analysis applied to fetal interphase cells obtained by chorionic villus sampling or amniocentesis. The choice of FISH was solely determined by prospective parents after formal genetic counselling concerning the advantages and disadvantages of FISH analysis. Excluding known familial chromosome aberrations, if FISH analysis revealed normal signals, there was an overall residual risk of 1 in 149 for an undetectable chromosome aberration. This risk varied according to the indication for prenatal diagnosis: 1 in 177 for women of advanced maternal age; 1 in 60 for women at increased risk for Down syndrome based on maternal serum screening; and, 1 in 43 for women whose ultrasound examination revealed fetal anomalies. There were 20 cases of discordance between the FISH results and standard karyotype analysis: four were the outcome of a failure to apply the appropriate FISH probe; 16 were not detectable by the available FISH probes. Of these 16, nine were chromosome abnormalities with clinical significance and seven were familial. If FISH is to become a standard part of prenatal genetic diagnosis, genetic counselling that is sensitive to patient health needs must be based on accurate information about the biological and obstetrical implications of the results of FISH analysis.

Indeterminate-cell histiocytosis: immunophenotypic and cytogenetic findings in an infant

BACKGROUND

The authors report the immunohistochemical, ultrastructural, and cytogenetic findings in a case of malignant histiocytic proliferation in an infant.

PROCEDURE

The patient presented initially with bone lesions without skin or systemic involvement. Multiple biopsies were studied extensively by immunohistochemistry and electron microscopy. Cytogenetic studies of cell cultures supplemented with granulocyte-monocyte colony stimulating factor (GM-CSF) were also performed.

RESULTS

Morphologically, the cells resembled Langerhans cells, although with greater pleomorphism, as evinced by cells with usual polylobated nuclei. These cells expressed markers for macrophages and antigen presenting cells and were CD1a- and S-100-positive, but lacked Birbeck granules. The cells grown in culture supplemented with GM-CSF showed a unique combination of numerical and structural abnormalities affecting chromosomes 1, 6, 8, and 10. The disease followed a malignant course leading to the patient's demise despite aggressive chemotherapy and bone marrow transplant.

CONCLUSIONS

The findings suggest a malignant hematopoietic stem-cell neoplasm with a capacity for macrophage or dendritic-cell differentiation. Morphology and immunophenotypic features place this neoplasm within the group recently conceptualized as indeterminate-cell histiocytosis.

Factors associated with maternal cell contamination in amniocentesis samples as evaluated by fluorescent in situ hybridization

OBJECTIVE

To determine which patient- and procedure-related factors contribute to maternal cell contamination in uncultured amniocentesis fluid.

METHODS

One hundred thirty amniotic fluid (AF) samples were obtained by three operator groups: maternal-fetal medicine faculty (n=50), general obstetrician gynecologists (n=50), and obstetrics and gynecology residents supervised by maternal-fetal medicine faculty (n=30). These groups were designated "most," "intermediate," and "least experience," respectively. Study variables were recorded at the time of the procedure. Amniotic fluid cells from male fetuses underwent fluorescent in situ hybridization. Maternal cell contamination was calculated by analyzing 100 cells and determining the number of XX and XY cells. A control system was created to validate the methods used for AF processing and cell counting.

RESULTS

Median maternal cell contamination was 2.0%. Maternal cell contamination did not vary with body mass index (r=-.13, P=.14), gestational age (r=.08, P=.35), or placental location (P=.55). Maternal cell contamination was significantly elevated with placental penetration (6.0% compared with 1.0%, P < .001), two passes (27.5% compared with 2.0%, P=.002), blood-tinged fluid color (14.0% compared with 2.0%, P < .001), and operator inexperience ("intermediate experience" compared with "most experience," 4.5% compared with 1.0%, P=.026). Maternal cell contamination did not differ between the "most experience" and "least experience" groups (1.0% compared with 2.0%, not significant). Concordance between detected and actual maternal cell contamination in the control system was extremely high (concordance coefficient=0.98, P=.008), confirming the validity of the techniques used.

CONCLUSION

Our techniques of cell counting and maternal cell contamination calculation are accurate. Maternal cell contamination is increased with placental penetration, two passes, and operator inexperience. However, with expert supervision, inexperienced physicians can perform amniocentesis without an increase in maternal cell contamination.

Hybridization of chromosome 18 alpha-satellite DNA probe to chromosome 22

Fluorescence in situ hybridization (FISH) of uncultured chorionic villus diploid cells with a chromosome 18 alpha-satellite DNA probe (D18Z1) revealed a third small signal in addition to two large signals. FISH analysis of diploid metaphase cells from cultured chorionic villus cells and from maternal lymphocytes revealed that the third signal resulted from hybridization to the centromere of chromosome 22. This is the first report of a variant involving D18Z1 detected by FISH and of hybridization of alpha-satellite from a sub-metacentric chromosome to the centromere of an acrocentric chromosome. We propose that this inherited variant resulted from insertion of chromosome 18 specific alpha-satellite DNA sequences into the centromeric region of chromosome 22.

Clonal cytogenetic abnormalities in pediatric brain tumors: cytogenetic analysis and clinical correlation

The use of contemporary techniques in genetics has resulted in identifying a number of recurring abnormalities in pediatric brain tumors. This information has potential significance in the diagnosis and subtyping of these tumors. Although recurring genetic alterations have been identified in specific tumor types, there are some indications that pediatric brain tumors may be different cytogenetically from adult tumors. In addition, cytogenetic aberrations in certain tumors are associated with unfavorable outcome. In this report we present the cytogenetic characteristics of 14 brain tumors. The clinical outcome is correlated with cytogenetic abnormalities. Clonal abnormalities were observed in 6 of 14 (43%) tumors. All 7 cases had abnormalities specific to histologic subtype. Five of 6 cases with clonal abnormalities (83%) and 2 of 8 with a normal karyotype (25%) were observed in patients with poor prognosis. We also describe the cytogenetic aberrations associated with progression in a rare pediatric brain tumor. This data suggests that cytogenetic analysis of pediatric brain tumors may not be entirely different from their adult counterpart and like the latter may be clinically relevant not only in diagnosis but also as a prognostic indicator.

dic(5;17): a recurring abnormality in malignant myeloid disorders associated with mutations of TP53

We have identified three unbalanced translocations involving chromosomes 5 and 17, der(5)t(5;17), der(17)t(5;17), and dic(5;17), in the malignant cells from 17 patients with myeloid neoplasms. Six patients had a primary myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) de novo; ten patients had therapy-related MDS and/or AML (t-MDS/t-AML), and one patient had chronic myelogenous leukemia in myeloid blast phase. Two of the six patients with MDS or AML de novo had extensive exposure to industrial solvents, and one patient had Seckel syndrome. The primary diagnoses for the ten patients with t-MDS/t-AML were breast carcinoma and Hodgkin's disease in two patients each, and non-Hodgkin's lymphoma, multiple myeloma, chronic lymphocytic leukemia, ovarian carcinoma, thyroid carcinoma, and rhabdomyosarcoma in one patient each. Four patients had received both prior chemotherapy and radiotherapy, four others received prior chemotherapy only, and the remaining two patients only prior radiotherapy. Fluorescence in situ hybridization of centromere-specific probes for chromosomes 5 and 17 revealed that a dicentric rearrangement was the most common (13/16 patients examined). The genetic consequences of these chromosomal rearrangements are partial monosomy for 5q and 17p. Two of six patients examined had point mutations in TP53, suggesting that loss of function of TP53 in addition to loss of a tumor suppressor gene on 5q may be involved in the pathogenesis of the malignant disease in some of these patients.

Recurring structural chromosome abnormalities in peripheral blood lymphocytes of patients with mycosis fungoides/Sézary syndrome

Cytogenetic analysis was performed on peripheral blood lymphocyte cultures from 19 patients with mycosis fungoides (MF)/Sézary syndrome (SS) stimulated with either phytohemagglutinin, a conventional mitogen, or a combination of interleukin-2 (IL-2) plus IL-7. The use of both PHA-stimulated and IL-2 plus IL-7-stimulated cultures enhanced the ability to identify clonal abnormalities. Clonal abnormalities were observed in 11 patients (53%) including one with monosomy for the sex chromosome as the sole abnormality. Five of the 11 patients with clonal abnormalities had normal peripheral white blood cell counts, indicating detectability of clones in the absence of frankly leukemic disease. The presence of clonal abnormalities correlated with advanced stage disease and a significantly reduced survival duration from the time of cytogenetic studies. Clonal abnormalities involving chromosomes 1 and 8 were observed in six cases. In five cases with aberrations of chromosome 1, loss of material involved the region between 1p22 and 1p36. In an additional case, a reciprocal translocation involving 1p33 was observed. Clonal abnormalities involving chromosomes 10 and 17 were observed in 5 cases, clonal abnormalities involving chromosome 2 in 4 cases, and clonal abnormalities involving chromosomes 4, 5, 6, 9, 13, 15, 19, and 20 in 3 cases. In 2 cases a der(8)t(8;17)(p11;q11) was observed. Regions of the genome that encode T-cell receptors were not involved in abnormalities. The region between 1p22 and 1p36 is identified as a region of the genome that requires detailed analysis toward the identification of potential gene(s) involved in the process of malignant transformation and/or progression in MF/SS.

Pituitary adenoma and bilateral male breast cancer: an unusual association

An unusual case is presented of bilateral breast cancer in a male patient with a long history of endocrine dysfunction due to a prolactinoma. The role of abnormal endocrine function in the development of male breast cancer is reviewed. The strongest association between aberrant endocrine function and male breast cancer occurs in patients with Klinefelter's syndrome, who have an approximate 3% lifetime risk of developing breast cancer. Retrospective case-control studies indicate that both estrogen excess and androgen deficiency may be involved in male breast cancer. Clinical studies of estrogen, androgen, and prolactin levels in male breast cancer patients have yielded conflicting results, and the precise nature of the hormonal mechanisms involved in the development of male breast cancer remains to be defined.

A prospective study of the association between isolated fetal pyelectasis and chromosomal abnormality

OBJECTIVE

To determine the incidence of chromosomal abnormalities among fetuses with isolated pyelectasis.

METHODS

Between March 1991 and March 1994, 121 cases of isolated fetal pyelectasis were identified at our institution. Pyelectasis was defined as a renal pelvis anteroposterior diameter of at least 4 mm before 33 weeks' gestation, and at least 7 mm at 33 weeks or thereafter. Once identified, women were offered antenatal genetic testing; if they declined, consent was sought for umbilical cord blood studies at delivery.

RESULTS

Chromosomal evaluation was available in 99 women. Two chromosomal abnormalities were identified: one trisomy 21 and one mosaic 46, XY/47, XYY. The ages of the women were 32 and 28 years, respectively. Calculation of adjusted risks for Down syndrome and all chromosomal abnormalities indicated a 3.9-fold increase in Down syndrome risk and a 3.3-fold increase in risk for all chromosomal abnormalities in the presence of isolated fetal pyelectasis.

CONCLUSION

Isolated fetal pyelectasis is associated with increased risk, over that related to age, for both Down syndrome and all chromosomal abnormalities. These factors may be valuable in counseling individual patients regarding the appropriateness of amniocentesis.

Karyotype correlates with peripheral blood morphology and immunophenotype in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is recognized as a distinct entity. However, morphologic and immunophenotypic heterogeneity exist. Twenty-six patients with CLL were studied to investigate whether an association exists among peripheral blood karyotype, morphology and immunophenotype. Clonal cytogenetic abnormalities were detected in 14 patients (53%), using conventional karyotyping techniques in addition to fluorescence in situ hybridization (FISH) for chromosome 12. By FAB guidelines, 7 of the 8 patients (88%) with trisomy 12 had mixed cell morphology compared to only 3 of 18 (17%) without trisomy 12 (P = .004). One patient (12%) with trisomy 12 had lymphocyte morphology typical for CLL. Six of the eight (75%) with trisomy 12 had atypical immunophenotype including one or more of the following: strong CD20 expression, strong surface light chain expression, or absence of CD23 expression. Only 2 of the 18 patients (11%) without trisomy 12 had atypical immunophenotype (P = .005). None of the three patients with clonal structural abnormalities of chromosome 13q14 had mixed cell morphology or atypical immunophenotype. One of the 12 patients (8%) without clonal cytogenetic abnormalities had mixed cell morphology and one had atypical immunophenotype. This study suggests that a correlation exists among karyotype, morphology, and immunophenotype in CLL, and that CLL subgroups can be identified based on laboratory parameters. Although normal karyotypes or clonal structural abnormalities of 13q14 are associated with morphology and immunophenotype considered typical for CLL, trisomy 12 is associated with mixed cell morphology and atypical immunophenotype. These findings may have implications for evaluating variation in both disease course and response to emerging therapies.

Male and female flowers of the dioecious plant sorrel show different patterns of MADS box gene expression

Male and female flowers of the dioecious plant sorrel (Rumex acetosa) each produce three whorls of developed floral organs: two similar whorls of three perianth segments and either six stamens (in the male) or a gynoecium consisting of a fertile carpel and two sterile carpels (in the female). In the developing male flower, there is no significant proliferation of cells in the center of the flower, in the position normally occupied by the carpels of a hermaphrodite plant. In the female flower, small stamen primordia are formed. To determine whether the organ differences are associated with differences in the expression of organ identity genes, cDNA clones representing the putative homologs of B and C function MADS box genes were isolated and used in an in situ hybridization analysis. The expression of RAD1 and RAD2 (two different DEFICIENS homologs) in males and females was confined to the stamen whorl; the lack of expression in the second, inner perianth whorl correlated with the sepaloid nature of the inner whorl of perianth segments. Expression of RAP1 (a PLENA homolog) occurred in the carpel and stamen whorls in very young flower primordia from both males and females. However, as soon as the inappropriate set of organs ceased to develop, RAP1 expression became undetectable in those organs. The absence of expression of RAP1 may be the cause of the arrest in organ development or may be a consequence.

Characterization of marker chromosomes by microdissection and fluorescence in situ hybridization

We characterized by microdissection and fluorescence in situ hybridization (FISH) two marker chromosomes: (1) a de novo, acrocentric marker chromosome detected in 88 per cent of the amniotic fluid cells of one of two physically and developmentally normal twins; and (2) a metacentric marker chromosome present in a phenotypically normal female. Analysis of FISH probes developed from the marker chromosomes indicated that the marker chromosomes in cases 1 and 2 were del(14)(q11) and a derivative chromosome from a Robertsonian translocation, respectively. Microdissection in combination with FISH may prove to be a valuable technique in determining the chromosomal origin of de novo marker chromosomes and unbalanced structural rearrangements detected during prenatal diagnosis.

Partial characterization of the Nicotiana tabacum actin gene family: evidence for pollen-specific expression of one of the gene family members

The actin gene family of Nicotiana tabacum has been partially characterised by Southern hybridisation and by isolating lambda EMBL4 recombinants from a genomic library having homology to the soybean actin gene, Sac3. The number of actin genes with homology to Sac3 is estimated at between 20 to 30, based on Southern hybridisation and library screening, though the total gene family may be larger. Twenty-four recombinant lambda clones were isolated, 18 had unique restriction profiles and from these, 2 clones, Tac9 and Tac25, were selected for further study. The region of Tac25 hybridizing to Sac3 was sequenced and shown to contain an open reading frame (ORF) with homology to actin. Partial sequencing of Tac9 revealed a sequence with homology to the third exon of Tac25 and Sac3. The two tobacco actin sequences were compared to other reported actin gene sequences; Tac25 was closely related to the allelic potato actins, Pac58 and Pac85, while Tac9 was more related to Pac79 than to other plant actins. Northern hybridisation analysis showed that while Tac9 detected actin transcripts in RNA from root, leaf, stigma and pollen, Tac25 transcripts were only detected in pollen RNA.

Extraordinary stability of enzymes dried in trehalose: simplified molecular biology

We show that extremely fragile biomolecules such as DNA restriction and modifying enzymes can be dried in vitro in the presence of trehalose with no loss of activity, even after prolonged storage. A remarkable and unexpected property of the dried enzyme preparations is their ability to withstand prolonged exposure to temperatures as high as +70 degrees C. This stability is unique to trehalose and is not found with other sugars irrespective of their physical or chemical properties. The immediate significance of these observations is the ability to convert enzymes used in molecular biology into stable reagents. The indefinite stability and high temperature tolerance of these dried enzymes should permit the design of convenient formats that may be of particular significance in the automation of genome mapping and sequencing projects. The stabilization of a wide range of biomolecules by trehalose also has practical implications for a number of areas ranging from basic science, through healthcare and agriculture, to bio-electronics.

Clinical, morphologic, and cytogenetic characteristics of 26 patients with acute erythroblastic leukemia

We have performed a retrospective analysis of the clinical, morphologic, and cytogenetic findings in 26 patients diagnosed between January 1969 and September 1991 with acute erythroblastic leukemia de novo (EL or AML-M6). Clonal chromosomal abnormalities were found in 20 (77%) patients (95% confidence interval [CI], 61% to 93%). Loss of all or part of the long arm (q) of chromosomes 5 and/or 7 was observed in 17 (65%) patients (95% CI, 47% to 83%). In addition, the karyotypes were often complex, with multiple abnormalities and subclones. Among the remaining nine patients, six had a normal karyotype and one each had trisomy 8, t(3;3), or t(3;5). The overall frequency of abnormalities of chromosomes 5 and/or 7 observed in our M6 patients is similar to that observed in our patients with therapy-related acute myeloid leukemia (t-AML; 99 of 129 patients, 77%), but substantially higher than that noted in our other patients with AML de novo (French-American-British [FAB] subtypes M1-M5: 52 of 334 patients, 16%). Our M6 patients with abnormalities of chromosomes 5 and/or 7 were older and had a shorter median survival (16 v 77 weeks [P = .005]) than did the M6 patients without these abnormalities. We found no correlation between morphologic features and either cytogenetic abnormalities or clinical outcome. Of note was the finding that the percentage of myeloblasts, which may account for only a small fraction of the total marrow elements when the revised FAB criteria are applied, had no bearing on prognosis. We conclude that acute erythroblastic leukemia, when defined by morphologic criteria, consists of two distinctive subgroups: one group tends to be older, has complex cytogenetic abnormalities, especially of chromosomes 5 and/or 7, and shares biologic and clinical features with t-AML; the other group, with simple or no detectable cytogenetic abnormalities, has a more favorable prognosis when treated with intensive chemotherapy.

Cytogenetic characterization of B-cell lymphomas from severe combined immunodeficiency disease mice given injections of lymphocytes from Epstein-Barr virus-positive donors

We analyzed the karyotype of 27 B-cell lymphomas of human origin that developed in mice with severe combined immunodeficiency disease following the injection of peripheral blood leukocytes from Epstein-Barr virus-seropositive donors. Three tumors had clonal abnormalities detected with conventional techniques, 2 had trisomy 11, and 1 had a del(6)(q21q25). One other tumor had trisomy 11 detected with fluorescence in situ hybridization. Twelve tumors had a normal karyotype, 11 tumors had nonclonal abnormalities (which included trisomy 9 or 12 in 3 or 2 tumors, respectively), and one tumor had a karyotype of 92,XXXX(75%)/46,XX(25%) by conventional cytogenetic analysis. Trisomy for chromosomes, 9, 11, and 12 are recurring abnormalities that have been observed in lymphomas associated with an immunocompromised state. Clonal or nonclonal abnormalities were observed in 8 of 11 tumors derived from 3 donors whose peripheral lymphocytes induced a high incidence of tumors in mice with severe combined immunodeficiency disease compared with a clonal abnormality and 2 nonclonal abnormal cells in 2 of 5 tumors derived from 3 donors whose lymphocytes induced an intermediate to low incidence. These observations suggest an association between a higher incidence of karyotypically abnormal cells in lymphomas and the increased tumorigenic potential of the lymphocytes that induced these tumors.

A physical and genetic linkage map of the distal long arm of human chromosome 5

By in situ hybridization of probes for three cloned genes and eight genetically-linked polymorphic DNA markers, we have prepared a physical map of the distal long arm of chromosome 5. These results, together with the localizations of 11 genes and the genetic linkage map reported previously by us and by other investigators, represent a map that spans 55 cM.

t(3;21)(q26;q22): a recurring chromosomal abnormality in therapy-related myelodysplastic syndrome and acute myeloid leukemia

We have identified an identical reciprocal translocation between the long arms of chromosomes 3 and 21 with breakpoints at bands 3q26 and 21q22, [t(3;21)(q26;q22)], in the malignant cells from five adult patients with therapy-related myelodysplastic syndrome (t-MDS) or acute myeloid leukemia (t-AML). Primary diagnoses were Hodgkin's disease in two patients and ovarian carcinoma, breast cancer, and polycythemia vera in one patient each. Patients had been treated with chemotherapy including an alkylating agent for their primary disease 1 to 18 years before the development of t-MDS or t-AML. We have not observed the t(3;21) in over 1,500 patients with a myelodysplastic syndrome or acute myeloid leukemia arising de novo or in over 1,000 patients with lymphoid malignancies. We have previously reported that the t(3;21) occurs in Philadelphia chromosome-positive chronic myelogenous leukemia (CML). Thus, the t(3;21) appears to be limited to t-MDS/t-AML and CML, both of which represent malignant disorders of an early hematopoietic precursor cell. These results provide a new focus for the study of therapy-related leukemia at the molecular level.

Clinical, morphologic, and cytogenetic characteristics of patients with lymphoid malignancies characterized by both t(14;18)(q32;q21) and t(8;14)(q24;q32) or t(8;22)(q24;q11)

Six patients with an aggressive leukemia/lymphoma disorder had a t(14;18) as well as either a t(8;14) (three patients) or a t(8;22) (three patients). Leukemia cells from all three patients with the t(8;22) had a mature B cell phenotype (Smlg + and TdT-), whereas two of three patients with the t(8;14) had a pre-B phenotype and were Smlg-. None of the patients with the t(8;22) had a prior history of follicular lymphoma, whereas two of the three patients with the t(8;14) had had a follicular lymphoma. The clinical, cytogenetic, and morphologic characteristics of these six patients along with eight previously reported cases with both the t(14;18) and the t(8;14), the t(8;22) or the t(2;8) are discussed.

Interstitial deletion of chromosome 5, del(5q), in a newborn with Down syndrome and an unusual hematologic disorder

A newborn with Down syndrome was noted on the 1st day of life to have an elevated white blood cell count of 79,900/mm3 with 62% lymphoblasts and a platelet count of 61,000/mm3, consistent with either transient myeloproliferative disorder of Down syndrome (TMD) or acute leukemia. Karyotype analysis of a bone marrow aspirate revealed that 20% of the cells had a 47,XY, +21 karyotype, and 80% had a 47,XY, +21, del(5)(q13q31) complement. Cytochemical and immunophenotyping of the peripheral blasts were consistent with the presence of an acute undifferentiated precursor blast clone. Results of clonogenic assays of hematopoietic progenitors from this patient's bone marrow were similar to those of patients with TMD. This patient's hematologic abnormalities resolved spontaneously without treatment by week 10 of life. This is the first report of an interstitial deletion of 5q associated with a hematologic abnormality present in an infant at birth.

Chromosomal abnormalities in Hodgkin's disease

In the hematologic malignant diseases, specific cytogenetic abnormalities correlate with clinical, morphologic, and immunophenotypic features. Although relatively little is known regarding the karyotypic pattern of Hodgkin's disease, it is clear that the involvement of specific chromosomes in numerical and structural abnormalities is nonrandom. Hyperdiploidy is a characteristic feature of Hodgkin's disease and is observed in 70 per cent of tumors that have an abnormal karyotype. A gain of chromosomes 1, 2, 5, 12, and 21 is a recurring numerical abnormality; structural rearrangements involving chromosome 1 are frequently observed. Perhaps as a result of the relatively small number of cases that have been analyzed, recurring structural abnormalities have not yet been identified; it has also not been possible to determine whether the various histologic subtypes of Hodgkin's disease are characterized by unique abnormalities. The prognostic significance of cytogenetic abnormalities in Hodgkin's disease is unclear; however, preliminary results suggest that the karyotype may have prognostic importance in this disease. The correlation of the cytogenetic pattern with the clinical and morphologic features will be essential in evaluating the clinical and biologic significance of chromosomal abnormalities in Hodgkin's disease.

Cytogenetic abnormalities in a secondary lymphoma complicating cardiac transplantation

We report a case of secondary lymphoma in the brain in a cardiac transplant recipient. Cytogenetic analysis revealed the presence of clonal cytogenetic abnormalities. Two clones with unrelated chromosomal abnormalities were noted; in both abnormal clones, trisomy for the long arm of chromosome 11 was observed. Our observations, combined with single cases previously reported, suggest that a gain of the long arm of chromosome 11 may represent a characteristic cytogenetic abnormality that is associated with secondary lymphoma.

Der(5)t(5;7)(q11.2;p11.2): a new recurring abnormality in malignant myeloid disorders

Complete or partial monosomy for the long arm of chromosomes 5 and/or 7 is frequently observed in malignant cells from patients with a therapy-related myelodysplastic syndrome (t-MDS) or therapy-related acute nonlymphocytic leukemia (t-ANLL). Partial monosomy is usually the result of a chromosomal deletion; however, unbalanced translocations have also been observed. We have identified one such translocation in three patients who had either t-ANLL or a primary MDS. The genetic consequences of this translocation [-5,-7,+der(5)t(5;7)(q11.2;p11.2)] are partial monosomy for the long arm of chromosome 5 and complete monosomy for the long arm of chromosome 7. Thus, this rearrangement may represent a new, recurring abnormality that is associated with malignant myeloid disorders.

Detection of mycoplasma contamination in tissue cultures by fluorescence microscopy

The in situ staining method of Chen (1977) for the detection of mycoplasma contaminants in tissue cultures was tested in cultures of human skin fibroblasts after controlled contamination with Mycoplasma arginini. It is concluded that this method is reliable only at infection rates of 100% or higher, i.e., at one mycoplasma or more per tissue-culture cell.