Investigation of the inhibitors of histone-lysine N-methyltransferase SETD2 for acute lymphoblastic leukaemia from traditional Chinese medicine.

Leukaemia is the leading cause of childhood malignancies. Recent research indicates that the SETD2 gene is associated with acute lymphoblastic leukaemia. This study aims to identify potential lead compounds from traditional Chinese medicine (TCM) using virtual screening for SET domain containing 2 (SETD2) protein against acute lymphoblastic leukaemia. Docking simulation was performed to determine potential candidates which obtain suitable docking poses in the binding domain of the SETD2 protein. We also performed molecular dynamics (MD) simulation to investigate the stability of docking poses of SETD2 protein complexes with the top three TCM candidates and a control. According to the results of docking and MD simulation, coniselin and coniferyl ferulate have high binding affinity and stable interactions with the SETD2 protein. Coniselin is isolated from the alcoholic extract of Comiselinum vaginatum Thell. Coniferyl ferulate can be isolated from Angelica sinensis, Poria cocos (Schw.) Wolf, and Notopterygium forbesii. Although S-adenosyl-L-homocysteine has more stable interactions with key residues in the binding domain than coniselin and coniferyl ferulate during MD simulation, the TCM compounds coniselin and coniferyl ferulate are still potential candidates as lead compounds for further study in the drug development process with the SETD2 protein against acute lymphoblastic leukaemia.

Primary myelodysplasia occurring in adults under 50 years old: a clinicopathologic study of 52 patients.

Although myelodysplastic syndromes (MDSs) are generally thought to be diseases of elderly patients, younger patients also have rarely been diagnosed with MDS. This is a report of the clinical, morphologic and cytogenetic features of 52 cases of primary MDS occurring in adults under the age of 50 years. Cases secondary to chemotherapy or radiotherapy were excluded. There were 31 males and 21 females. The median age at presentation was 39 years (range, 18 to 49 years). The interval between onset of symptoms and diagnosis was brief (median, 4 weeks; range, 1-32 weeks). Of the 49 patients for whom information about duration of symptoms was available, 13 (27%) were asymptomatic. Forty-two (81%) of the patients were classified using FAB criteria for blood and bone marrow morphology: refractory anemia (RA), 11; refractory anemia with ringed sideroblasts (RARS), four; refractory anemia with excess blasts (RAEB), 12; chronic myelomonocytic leukemia (CMML), three; refractory anemia with excess blasts in transformation (RAEB-T), 12 patients. Ten patients could not be categorized. Abnormalities involving chromosome 7 was the most frequent cytogenetic abnormality (31%). Partial chromosomal deletion and chromosome gain were also common abnormalities (22% and 9%, respectively). Translocations accounted for only 9% of the main cytogenetic abnormalities encountered in this patient population. For the 49 patients for whom information regarding AML transformation was available, 23 (47%) progressed to acute myeloid leukemia, with an overall median time to progression of 2 months (range 3 weeks to 3 years). In each category except for RARS, approximately half of the patients progressed, with a slightly less median time to progression in RAEB-T than for the other subtypes of MDS. Thirteen patients underwent bone marrow transplantation at the time of presentation of their disease.

Histological and immunohistochemical characterization of extranodal diffuse large-cell lymphomas with prominent spindle cell features.

AIMS: To describe five cases of diffuse large-cell lymphoma with prominent spindle cell components involving skin, nasal-ocular mucosa, and soft tissue. Because of the spindle cell morphology, such cases must be differentiated from true sarcomas arising in or metastasizing to soft tissue, skin, bone, lymph node, or other organs and sites. METHODS AND RESULTS: Formalin-fixed paraffin-embedded archival tissue from five consultation cases of diffuse large-cell lymphoma with prominent spindle cell features involving the skin, nasal-ocular mucosa, and soft tissue in three male and two female patients was studied by histology and immunohistochemistry. Clinicopathological findings were also reviewed for all the patients. By morphology, initial evaluation of the cases suggested spindle cell sarcoma in two cases, inflammatory pseudotumour in one case, large-cell lymphoma in another case, and one case was considered suspicious for malignant lymphoma. Immunohistochemistry demonstrated a B-cell lineage in four of the spindle cell lesions, with a diagnosis of primary cutaneous CD30+ anaplastic large cell lymphoma made for the fifth case. Four of five cases also showed actin reactivity. CONCLUSIONS: Although extremely rare, lymphomas with prominent spindle cell morphology can be encountered in daily surgical pathology practice, and should be included in the differential diagnosis of spindle cell lesions in skin and soft tissue. The observed actin reactivity in four of the five spindle cell lymphomas may lead to a misdiagnosis of leiomyosarcoma if lymphoid markers are not included in the immunohistochemical panel.

Diagnostic utility of microphthalmia transcription factor in malignant melanoma and other tumors.

The diagnosis of malignant melanoma is sometimes challenging. Immunohistochemistry for specific markers of melanocytic differentiation such as HMB-45 and Melan-A can be very valuable in proving melanocytic differentiation in poorly differentiated or spindled forms of melanoma. Microphthalmia-associated transcription factor (MiTF) is the most recently described and the only nuclear melanocytic marker. This article reviews the biology of MiTF and those published studies that have addressed its diagnostic sensitivity and specificity. MiTF may be very valuable for the diagnosis of melanoma, including desmoplastic variants; melanocytic soft tissue tumors, such as clear cell sarcoma; and the unusual group of tumors that show combined melanocytic and myoid differentiation, the perivascular epithelioid cell family of tumors (PEComas).

No significant association of Epstein-Barr virus infection with invasive breast carcinoma.

We studied 48 cases of invasive breast carcinoma for evidence of Epstein-Barr virus (EBV), which is associated with many human malignancies. In situ hybridization studies to detect the presence of EBV-encoded small nonpolyadenylated RNA (EBER)-1 were performed in paraffin sections. Immunohistochemical studies to detect EBV nuclear antigen (EBNA)-1, latent membrane protein (LMP)-1, and the transactivating immediate-early BZLF1 (ZEBRA) protein were also performed in paraffin sections. The presence of EBV genomic DNA was studied by polymerase chain reaction (PCR) amplification using sets of primers flanking the EBNA-4 and the EBV-LMP-1 genes in frozen tissues. Southern blot analysis using a probe flanking the EBV terminal repeat region was then attempted in cases that were PCR-positive. Five of 48 cases (10%) of breast carcinoma showed focal EBER-positive tumor cells. Twelve cases (25%) were positive for EBNA-1 by immunohistochemistry, all but one different from the EBER-positive cases. None of the cases were positive for LMP-1 or ZEBRA protein by immunohistochemistry. PCR studies for EBNA-4 and LMP-1 were each positive in five cases (including three cases in common). However, Southern blot studies successfully performed in all but one of the PCR-positive cases were completely negative. The identification of EBV by any methodology was not correlated with tumor size, grade, or lymph node status. This study demonstrated evidence of EBV infection in tissues involved by invasive breast carcinomas in a significant subset of cases. However, the lack of localization of EBV infection to a significant population of the tumor cells in any case, the negativity by Southern blot hybridization, and the lack of expression of multiple antigens in any case strongly argue against a significant role for EBV in the pathogenesis of breast carcinoma.

The effects of arecoline on the release of cytokines using cultured peripheral blood mononuclear cells from patients with oral mucous diseases.

In Taiwan there is a significant correlation between oral precancer diseases and oral cancer associated with the betel quid chewing habit. The carcinogenic components of betel quid are arecoline, arecaidine and safrole. However, it is unknown whether these substances influence the immune functions. This study investigated the effects of betel quid on the immune system using cultured peripheral blood mononuclear cells from patients with oral mucous diseases. In our experiment, mononuclear cells from 10 normal persons, 12 patients with precancer lesions, and 16 patients with squamous cell carcinoma were separated from blood samples and cultured. After stimulation by arecoline, the amounts of IL-2, TNF-alpha, TGF-beta and IFN-gamma secreted by mononuclear cells were measured using the ELISA method. The results showed that IL-2, TNF-alpha, and TGF-beta were significantly lower in mononuclear cells of normal persons as stimulated by arecoline. The TGF-beta amount in cells from oral submucous fibrosis patients with betel quid chewing habit (OSF-B) was lower than normal persons or patients who had long term betel quid chewing habit but were without oral mucosal diseases (N-B), and was also lower than the squamous cell carcinoma with betel quid chewing group (SCC-B). TNF-alpha was significantly lower in the squamous cell carcinoma with long term betel quid chewing group (SCC-B) than in normal persons. TNF-alpha was significantly higher in the squamous cell carcinoma without betel quid chewing group (SCC-N) than in normal persons and SCC-B groups. In addition, IFN-gamma was significantly lower in patients who had long term betel quid chewing but were without oral mucous lesions than the normal person and the OSF group. The results proved that betel quid influences cytokines production by mononuclear cells.

Utility of CD10 in distinguishing between endometrial stromal sarcoma and uterine smooth muscle tumors: an immunohistochemical comparison of 34 cases.

Endometrial stromal sarcoma (ESS), uterine cellular leiomyoma (UCL), and uterine leiomyosarcoma (ULS) are composed mainly of spindle cells that express similar antigens such as desmin, smooth muscle actin (SMA), and muscle-specific actin (MSA). The differential diagnosis of an ESS versus a uterine smooth muscle tumor or an extrauterine spindle cell sarcoma can be problematic based solely on clinical presentation, histologic assessment, or routine immunohistochemistry. Recently, we reported that normal endometrium, but not myometrium, as well as five cases of ESS, were positive for CD10. We now report the results of CD10 immunohistochemistry in an additional 11 cases of ESS (total 16 cases), 10 cases of UCL, and nine cases of ULS. CD10 immunoreactivity was detected in 16 of 16 cases of ESS (100%) as compared to only 2 of 10 cases of UCL (20%) and none of nine cases of ULS (0%). We compared the utility of CD10 immunoreactivity with that of desmin, SMA, MSA, estrogen receptor (ER), and inhibin in these tumors. Although the majority of cases of UCL and ULS were positive for SMA, MSA, and desmin, a substantial portion of cases of ESS were also positive for SMA, MSA, and desmin. We conclude that in combination with SMA, MSA, and desmin, CD10 is a useful immunohistochemical marker in the differential diagnosis of ESS versus UCL or ULS.

Development of a sandwich ELISA test for arginase measurement based on monoclonal antibodies.

Human arginase was purified from liver and two monoclonal antibodies (MAbs), HA1 and HA2, were produced by fusion of spleen cells from an arginase-immunized BALB/c mouse and the NS-1 myeloma cell line. Both MAbs were of the IgG3 subclass and contained the kappa light chain. HA1 inhibited arginase activity, suggesting that it binds to the arginase catalytic site. HA1 and a horseradish peroxidase-conjugated polyclonal rabbit anti-human arginase antibody were used to develop a sandwich enzyme-linked immunoadsorbent assay (ELISA) for the quantification of human arginase, which can be used in the 1 to 300 ng/mL range. Because of its sensitivity and specificity, this MAb can be successfully applied to the ELISA quantification of arginase in serum and culture supernatants.

Immunohistochemical detection of CD10 in paraffin sections of hematopoietic neoplasms: a comparison with flow cytometry detection in 56 cases.

Paraffin-section immunohistochemistry with heat-induced epitope retrieval using a newly characterized monoclonal antibody (clone 56C6) against the CD10 antigen was performed on 56 hematopoietic tumors previously studied for CD10 expression by flow cytometry. The cases included 33 precursor B-lymphoblastic leukemias, 10 acute myeloid leukemias, five precursor T-lymphoblastic leukemias, five follicular lymphomas, and three Burkitt cell leukemias. Forty of the 56 cases were CD10 positive by flow cytometry studies, including all five follicular lymphomas (100%); 30 of 33 (91%) cases of precursor B-lymphoblastic leukemias, two of three (66%) cases of Burkitt cell leukemias, two of five (40%) cases of precursor T-lymphoblastic leukemias, and none of the 10 cases of acute myeloid leukemia. Thirty-nine of the 40 (97%) flow cytometric CD10-positive cases also expressed CD10 by immunohistochemistry in formalin- or B5-fixed, paraffin-embedded tissue, with only one case of precursor B-lymphoblastic leukemia being positive by flow cytometry and negative by immunohistochemistry. The 16 CD10-negative flow cytometry specimens were all also negative by immunohistochemistry. Thirty-seven CD10 immunohistochemistry positive cases showed a diffuse membranous staining pattern and two cases demonstrated a Golgi staining pattern. The fixation methods (10% neutral buffered formalin versus B5) and decalcification did not affect the CD10 immunostaining results. This study demonstrates that the new CD10 monoclonal antibody clone 56C6 is a reliable marker for detection of CD10 antigen expression in formalin-and B5-fixed paraffin-embedded tissue after heat-induced epitope retrieval when compared with flow cytometry detection of fresh tissue samples.

Immunophenotyping of hematopoietic neoplasms.

Advances in the staging and treatment of hematopoietic neoplasms have necessitated a high degree of accuracy in the diagnosis and classification of these tumors. A greater degree of diagnostic precision has resulted from recent advances in immunophenotyping and genotyping of hematopoietic neoplasms. This review discusses several new immunohistochemical reagents, many of which are derived from results of molecular studies.

The use of archival bone marrow specimens in detecting B-cell non-Hodgkin's lymphomas using polymerase chain reaction methods.

The detection of B-cell non-Hodgkin's lymphoma (B-NHL) involving the bone marrow (BM) can be enhanced by assessing immunoglobulin heavy chain (IgH/JH) gene rearrangement using PCR. While the fresh BM aspirate has been the most commonly used specimen, the utility of archival BM tissues has not been extensively evaluated. We studied the BM from 13 patients with nodal B-NHL (7 low-grade and 6 intermediate grade), which were categorized into three groups based on the histologic finding of lymphoma (H) and the presence of a monoclonal IgH/JH band by PCR using fresh BM aspirates (M): (1) H(+)/M(+), 4 cases; (2) H(+)/M(-), 4 cases; and (3) H(equivocal)/M(-), 5 cases. Archival tissues available for study included paraffin-embedded trephine biopsy (TB)/aspirate clots (AC) and air-dried aspirate smears (AS). All TB (13/13) and a subset of AC (5/13) were B5-fixed, and all these tissues failed to yield analyzable DNA. In contrast, sufficient DNA was consistently obtained in AC that were formalin-fixed (8/13). Of these 8 cases, 2/3 of group 1, 3/3 of group 2, and 0/2 of group 3 had a monoclonal IgH band. Using DNA extracted from microdissected lymphoid aggregates morphologically evident in the AC sections, additional positive cases were identified: 1/3 of group 1 and 2/2 of group 3. In those 5 cases that did not have formalin-fixed TB/AC, sufficient DNA was extracted from AS in all cases; one additional positive case was identified in group 1. Overall, 4/4 (100%) of group 1, 3/4 (75%) of group 2, and 2/5 (40%) of group 3 showed molecular evidence of lymphoma. To conclude, archival BM specimens are a useful source of DNA for molecular detection of B-NHL involvement, and formalin appears to be a better fixative than B5. The use of these samples may improve the overall detection sensitivity.

Nasal glomus tumors: report of two cases with emphasis on immunohistochemical features and differential diagnosis.

We describe 2 cases of nasal glomus tumor that presented as nasal polyps. Grossly, each of the polypectomy specimens consisted of small fragments of polypoid soft tissue with glistening mucosa. Histopathological examination of each of the specimens showed sheets and nests of monomorphic round cells intimately associated with capillary-sized blood vessels. The tumor cells were strongly cytoplasmic positive for vimentin, smooth-muscle specific actin, muscle-specific actin, and CD34. Collagen IV showed pericellular positivity. Nasal glomus tumors are extremely rare and represent less than 0.5% of nasal nonepithelial tumors. Nasal polyps are common surgical pathological specimens, with the majority of nasal polyps being inflammatory polyps or a respiratory epithelial proliferation. Histologically, many nasal polyps show vascular proliferation with an inflammatory cell infiltrate, which may be confused with the rare glomus tumor. In addition, other nasal vascular tumors, in particular nasal hemangiopericytoma and neural tumors, may histologically mimic nasal glomus tumors.

Epstein-Barr virus (EBV) nuclear antigen (EBNA)-4 mutation in EBV-associated malignancies in three different populations.

Different ethnic groups with a high human leukocyte antigen (HLA)-A11 prevalence have been shown to experience a high rate of Epstein-Barr virus (EBV) infection, EBV-associated malignancies, and Epstein-Barr nuclear antigen (EBNA)-4 mutations. The epitopes 399-408 and 416-424 of EBNA-4 are major antigenic epitopes that elicit an HLA-A11 cytotoxic T lymphocyte (CTL) response to EBV infection. Mutations selectively involving one or more nucleotide residues in these epitopes affect the antigenicity of EBNA-4, because the mutant EBV strains are not recognized by the HLA-A11-restricted CTLs. To investigate these mutations in common EBV-associated malignancies occurring in different populations, we studied the mutation rate of epitopes 399-408 and 416-424 of EBNA-4 in 25 cases of EBV-associated Hodgkin's disease (HD), nine cases of AIDS-related non-Hodgkin's lymphoma, and 37 cases of EBV-associated gastric carcinoma (GC) from the United States, Brazil, and Japan. We found one or more mutations in these two epitopes in 50% (6/12) of United States HD, 15% (2/13) of Brazilian HD, 50% (6/12) United States GC and 28% (7/25) Japanese GC, and 22% (2/9) of United States AIDS-lymphoma. Similar mutations were found in 30% (3/10) of United States reactive, 0% (0/6) of Brazilian reactive, and 25% (2/8) Japanese reactive tissues. The most frequent amino acid substitutions were virtually identical to those seen in previously reported isolates from EBV-associated nasopharyngeal carcinomas and Burkitt's lymphomas occurring in high prevalence HLA-A11 regions. However, only 2/28 (7%) mutations occurred in HLA-A11-positive patients. Our studies suggest that: 1) EBNA-4 mutations are a common phenomenon in EBV-associated HD, GC, and AIDS-lymphoma; 2) the mutation rate does not vary in these geographic areas and ethnic groups; 3) EBNA-4 mutations in EBV-associated United States and Brazilian HD, United States and Japanese GC, and United States AIDS lymphomas are not related to patients' HLA-A11 status.

EBNA-1 gene sequences in Brazilian and American patients with Hodgkin's disease.

We examined the types of Epstein-Barr virus-associated nuclear antigen-1 (EBNA-1) gene carboxy (C)-terminal mutations occurring in Hodgkin's disease (HD) and reactive tissues from two different geographic regions. Previously reported EBNA-1 C-terminal region amino acid sequence variants, based on the amino acid at codon 487, include Prototype (P)-ala, which is found in the B95.8-derived prototype virus, P-thr, Variant (V)-leu, V-val, and V-pro. Using polymerase chain reaction (PCR) to amplify portions of the EBNA-1 gene, followed by DNA sequencing, we found a single EBNA-1 gene sequence variant in each tissue, whether reactive or neoplastic and whether from Brazil or the United States. Variant EBNA-1 gene sequences were more common in both neoplastic and non-neoplastic tissues from different geographic areas than the so-called prototype sequence. In the 17 Brazilian HD cases, 4 cases had P-thr variants and 13 had V-leu variants. In the six reactive tissues from Brazil, one had a P-ala variant, two had P-thr variants, and three had V-leu variants. In the 12 American HD cases, 2 had P-ala variants, 6 had P-thr variants, and 4 had V-leu variants. The 11 American reactive tissues included 2 P-ala variants, 5 P-thr variants, and 4 V-leu variants. In both countries, there were similar variant EBNA-1 sequences present in normal tissues and HD cases. Compared with the P-ala and P-thr cases, the V-leu cases were more likely to have the 30-bp latent membrane protein 1 (LMP1) gene deletion (P = 0.0075). In addition, cases of HD with the V-leu were statistically associated with a substitution of asparagine for glutamine at codon 322 of the C-terminal portion of the LMP1 gene. Our results suggest that any variation in EBNA-1 gene sequence is caused by a polymorphism present in pre-existing viral strains in the underlying population, and not a mutation occurring during oncogenesis.

Peripheral T-cell lymphoma with Toutonlike tumor giant cells associated with HIV infection: report of two cases.

T-cell lymphoma in patients infected with HIV is much less common than B-cell lymphoma. We describe two cases of HIV-associated extranodal lymphoma that showed Toutonlike tumor giant cells and mononuclear large lymphoma cells. Both cell types expressed T-cell-associated antigens, including CD3, CD5, CD43, and CD45RO, and were CD4- and CD30-positive and negative for all B-lineage-associated antigens. Both cases showed T-cell receptor gamma chain gene rearrangements using the polymerase chain reaction and were negative for the Epstein-Barr virus by in situ hybridization. Despite the expression of CD30 by the multinucleated cells, both cases were negative for ALK1 by immunohistochemistry and failed to show evidence of the nucleophosmin-anaplastic lymphoma kinase fusion product characteristic of t(2;5) using the reverse-transcriptase polymerase chain reaction. Although rare, CD4-positive, T-cell lymphoma with Toutonlike giant cells may be a distinct type of HIV-associated malignant lymphoma.

Practical applications of immunohistochemistry in hematolymphoid neoplasms.

Immunohistochemistry plays a key role in the diagnosis and classification of hematolymphoid neoplasms. New cell and lineage markers are constantly being discovered and added to the existing long list of antibodies. In this review article we provide general information and new applications of the commonly used hematolymphoid markers. We also discuss the features and applications of some newly discovered markers, such as ALK, fascin, granzyme/perforin, and tryptase. There is no universal "panel" for the diagnosis of hematolymphoid neoplasms. However, in this review article, we provide suggested panels for a given hematolymphoid neoplasm that is based on our experience and that reported in the literature.

Frequency of CD43 expression in non-Hodgkin lymphoma. A survey of 742 cases and further characterization of rare CD43+ follicular lymphomas.

CD43 expression on B cells is an immunophenotypic feature suggestive of malignancy. In the light of its diagnostic importance, we performed a comprehensive survey of CD43 expression in various types of non-Hodgkin lymphoma (NHL) and determined the frequency of its expression in routinely fixed paraffin-embedded tissues. Tissue sections in 742 cases of NHL, pretreated by the heat-induced epitope retrieval technique, were immunostained using an anti-CD43 antibody. Three categories of CD43 positivity were found: (1) more than 90% of T-cell lymphoma, mantle cell lymphoma, B-cell small lymphocytic lymphoma, and Burkitt lymphoma cases were positive; (2) 20% to 40% of nodal and extranodal marginal zone lymphoma (MZL), diffuse large B-cell lymphoma, Burkitt-like B-cell lymphoma, and lymphoplasmacytoid lymphoma cases were positive; and (3) 0% to 6% of primary splenic MZL and various types of follicular lymphoma cases were positive. Most CD43+ follicular lymphomas were predominantly large cell type with focally diffuse areas; their follicular center cell origin in 4 of 8 cases was supported by the presence of CD10 immunoreactivity and/or t(14;18) fusion gene product. CD43 is frequently detectable in a subset of B-NHL, and, thus, it seems to be a highly sensitive marker for these tumors. CD43 also may be a useful marker for classifying B-cell NHLs by virtue of its differential expression in these tumors.

Acute lymphoblastic leukemia. Survey of immunophenotype, French-American-British classification, frequency of myeloid antigen expression, and karyotypic abnormalities in 210 pediatric and adult cases.

Immunophenotypic studies are essential to distinguish acute lymphoblastic leukemia (ALL) from minimally differentiated acute myeloid leukemia (AMLM0) and to classify ALL into immunologic subtypes. Frequently, immunophenotyping identifies myeloid antigen expression in ALL, causing a potential diagnostic problem. To evaluate the immunophenotype of ALL, we studied 210 cases of pediatric and adult ALL by flow cytometry and compared the results with the French-American-British (FAB) Cooperative Group classification and the karyotypic findings. Myeloid-associated antigens were expressed in 78 (45.6%) of precursor B-cell ALL cases. Pediatric precursor B ALLs had a higher frequency of myeloid antigen expression than did adult cases. All mature B-cell ALL cases were negative for TdT and myeloid antigens. Myeloid antigen expression was less frequent in T-cell ALL cases compared with precursor B-cell ALL cases. Of the 192 cases submitted for cytogenetic analysis, 147 were abnormal. The most common chromosomal translocation was the Philadelphia chromosome, which was more likely to have L2 blast morphology and a precursor B immunophenotype. Myeloid antigen expression was present in 70.8% of Ph-positive cases (P = .008). Chromosome rearrangements involving 11q23 also showed an increased frequency of myeloid antigen expression. Chromosome translocations involving regions of T-cell receptor genes were present in 24% of T-cell ALL cases. A high percentage of ALL cases, however, had various other cytogenetic abnormalities, many of which involved less well-studied chromosomal regions.

Untreated chronic lymphocytic leukemia concurrent with or followed by acute myelogenous leukemia or myelodysplastic syndrome. A report of five cases and review of the literature.

Although it has been known that patients with chronic lymphocytic leukemia (CLL) have a higher frequency of second malignant neoplasms, the development of acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) in these patients is extremely rare. Most reported cases have been therapy-related. In this article, we report the clinical and immunophenotypic features of 5 cases of untreated CLL concurrent with or followed by the development of AML or MDS. All 5 patients were men, with ages ranging from 57 to 87 years (mean, 73.8 years). Four patients had AML and 1 patient had refractory anemia with ringed sideroblasts. In the 4 cases of AML and CLL, 2 distinct cell populations (i.e., myeloblasts and lymphocytes) were identified morphologically and/or immunophenotypically. Our findings support that this rare concurrence of AML or MDS and untreated CLL may represent 2 separate disease processes.