Reticulum cell sarcoma of lymph node with mixed dendritic and fibroblastic features.

We report a case of clinically aggressive reticulum cell sarcoma with mixed follicular dendritic cell (FDC) and fibroblastic reticular cell (FRC) features. Histologically, the tumor was confined to lymph nodes occurring as a multifocal epithelioid and spindle cell proliferation with appreciable mitotic rate and numerous admixed non-neoplastic B-cells. Ultrastructural examination revealed elongated cells with prominent nucleoli, interdigitating cell processes and frequent desmosomes. These features are typical of FDC sarcoma. However, immunohistochemical stains showed no expression of antigens characteristic of FDCs, including CD21, CD23 and CD35. Cytogenetic characterization of this tumor, by conventional G-banding and multicolor spectral karyotyping, revealed multiple clonal chromosomal aberrations, including del(X)(p11.4) and add (21)(p11.2). Gene expression analysis by cDNA microarray of RNA obtained from short-term tumor cultures revealed high-level expression of a set of genes (including PDGF receptor-alpha and -beta, certain metalloproteinases, and CD105) that were also highly expressed in cultures of nodal FRC cultured from non-neoplastic lymph nodes. We propose that this tumor represents a nodal sarcoma with intermediate differentiation between FDCs and FRCs. This case adds to the diversity of tumors that may arise from lymph node stroma and supports a possible relationship between the FDC and FRC lineages.

Detection of trisomy 8 in philadelphia chromosome-positive CML patients using conventional cytogenetic and interphase fluorescence in situ hybridization techniques and its relation to c-myc involvement.

Trisomy 8 (+8) is a common clonal evolution marker for progression in chronic myelogenous leukemia. The relationship of +8 to various stages of t(9;22) leukemias is not firmly established. To explore this association we examined bone marrow (BM) cells from 10 Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) patients in different stages of the disease, using conventional cytogenetic technique(CCT) and interphase fluorescence in situ hybridization (FISH). FISH detection of chromosome 8 was accomplished using the D8Z2 (Oncor) probe specific for the centrometric region of chromosome 8. Five hundred interphase nuclei were counted for each patient. Three of the 10 patients were selected for detection of c-myc gene locus located in the 8q24.2-24.3 region using the L

A unique, complex variant philadelphia chromosome translocation in a patient with typical chronic myelogenous leukemia.

The Philadelphia (Ph) chromosome [der(22) t(9;22)(q34;q11)] is the characteristic chromosomal abnormality found in chronic myelogenous leukemia (CML). This chromosome has been reported in patients with other chromosomal abnormalities. In this study, we describe a patient with hematologically typical chronic-phase CML with an unusual and complex translocation involving chromosomes 9, 11, and 22. These complex translocations were identified by G-banded conventional cytogenetics and confirmed by fluorescence in situ hybridization (FISH) using whole chromosome painting probes (wcp). To the best of our knowledge, these are unique translocations involving the short and the long arms of chromosome 9 in 4 different translocations with the short arm of chromosome 11 and the long arm of chromosome 22.

Detection of chromosome 11q13 breakpoints by interphase fluorescence in situ hybridization. A useful ancillary method for the diagnosis of mantle cell lymphoma.

We assessed cytologic specimens from 11 mantle cell lymphomas (MCLs) and 32 other B-cell non-Hodgkin lymphomas (NHLs) for 11q13 breakpoints using a 2-color fluorescence in situ hybridization (FISH) assay that uses an 11q13 probe centered on the CCND1 gene and a centromeric chromosome 11 probe (CEP11). The number of nuclei in 200 cells were counted, and results were expressed as an 11q13/CEP11 ratio. All MCLs showed a high percentage of interphase nuclei with 3 or more 11q13 signals (mean, 74.8%; range 57%-90%). In contrast, in other B-cell NHLs the mean percentage of cells with 3 or more 11q13 signals was 9.2%. All MCLs had an elevated 11q13/CEP11 ratio (mean, 1.38). The mean ratio for other B-cell NHLs was 0.99. Two non-MCL cases, 1 large B-cell and 1 B-cell unclassified NHL, had high 11q13/CEP11 ratios of 1.15 and 1.30, respectively. Conventional cytogenetic analysis performed on the former case revealed a t(5;11)(q31;q13). Interphase FISH analysis using 11q13 and CEP11 probes is a convenient ancillary method for assisting in the diagnosis of MCL. This commercially available assay is simple to use on cytology or imprint specimens, and results can be obtained within 24 hours.

Numeric chromosomal abnormalities in small lymphocytic and transformed large cell lymphomas detected by fluorescence in situ hybridization of fine-needle aspiration biopsies.

BACKGROUND: Chromosomal abnormalities in some lymphomas are associated with a poor prognosis. Trisomy 12 and deletions of chromosome 13 have been described in small lymphocytic lymphoma (SLL). To determine whether chromosomal aberrations could be detected by fluorescence in situ hybridization (FISH) on fine-needle aspiration biopsies (FNABs), we analyzed and compared specimens from seven patients with SLL and nine patients with a history of SLL that had transformed to large cell lymphoma. METHODS: DNA probes specific to chromosome 12 and the chromosome 13/RB-1 gene locus were used for in situ hybridization on interphase cell nuclei. The cytologic features, ploidy, proliferation index, and conventional cytogenetic analysis findings were correlated with the FISH results. RESULTS: Trisomy 12 was detected in 2 (29%) of the 7 cases of SLL and 2 (22%) of the 9 cases of transformed large cell lymphoma. Deletion of chromosome 13/RB-1 was present in 3 (43%) of 7 cases of SLL and 3 (33%) of 9 cases of transformed large cell lymphoma. CONCLUSIONS: This study showed that interphase cytogenetic analysis by FISH is feasible on FNAB specimens. Trisomy 12 and deletions of chromosome 13/RB-1 were present in some cases of SLL and transformed large cell lymphoma, and the presence of these chromosomal abnormalities did not correlate with transformation to a higher grade of lymphoma.

Early detection of relapse by hypermetaphase fluorescence in situ hybridization after allogeneic bone marrow transplantation for chronic myeloid leukemia.

PURPOSE: Standard G-band cytogenetic analysis (CG) provides information on approximately 25 metaphases for monitoring the presence of Philadelphia chromosome positive (Ph+) cells in chronic myelogenous leukemia (CML) patients, making the detection of a low frequency of Ph+ cells problematic. The purpose of this study was to improve the detection of a low frequency of Ph+ cells. PATIENTS AND METHODS: We combined fluorescence in situ hybridization (FISH) with long-term colcemid exposure, capturing several hundred metaphases in bone marrow cultures (hypermetaphase FISH [HMF]). Using probes that identify Ph+ cells, HMF was compared with CG analysis in the follow-up evaluations of 51 patients with CML at various time points after allogeneic bone marrow transplant (BMT). RESULTS: Thirty-five patients never showed the presence of Ph+ cells by either method. In four patients, high frequencies of Ph+ cells were detected by both methods. In the remaining 12 patients, Ph+ cells were detected by HMF at time points after BMT when they were not detected by CG. In seven of the 12 patients, low but statistically significant frequencies of Ph+ cells (0.37% to 5.20%) were detected 3 months or later after BMT, and when no intervention was initiated, all seven patients later relapsed. Based on those data, an eighth patient with mixed chimerism and a similar HMF-detected Ph+ frequency (1.8% at 27 months after BMT) was reinfused with donor lymphocytes and achieved remission with 0% Ph+ cells studied by HMF (up to 50 months after BMT). Ph+ cells detected by HMF but not by CG less than 3 months after BMT disappeared on later examination in two of four patients. After detection of Ph+ cells by HMF only, the median time to cytogenetic progression (detection of Ph+ cells by CG) was 101 days. CONCLUSION: The results demonstrate the ability of HMF to detect low but clinically relevant levels of leukemic cells not detected by CG in transplant patients. The data indicate that HMF can detect low levels of Ph+ cells before standard cytogenetics at a time that may be useful in monitoring disease status and planning clinical interventions.

Chromosomal abnormalities in acute leukemias.

Conventional cytogenetic techniques are the standard for the diagnosis and follow-up of patients with AML and ALL. Some characteristic translocations associated with various groups of AML diagnoses, such as t(8;21), t(15;17), and inv(16) for M2, M3, and M4eo, respectively, have been recognized for years. The most common cytogenetic abnormality found in childhood ALL and hyperdiploid adult ALL is t(9;22). Future directions include increased use of FISH and molecular diagnostic techniques. The clinical cytogenetics laboratory plays a major role in the diagnosis and management of AML and ALL.

Cytogenetics as an aid in the diagnosis of lymphomas.

Multiple classifications of lymphomas are available. Generally, distinctions are made to identify low, intermediate, and high-risk groups. Histopathologic differentiation is at times difficult. The revised European-American lymphoma classification (REAL) uses histology, clusters of differentiation markers, histochemistry, and cytogenetics for definitive identification. This work reviews the karyotypic and FISH (fluorescent in situ hybridization) findings in some common lymphomas. B-Cell lymphomas, which make up approximately 85-90% of lymphomas, are associated with cytogenetic changes of +12, 13q14, 14q32, 2p11, and 22q13. Translocations help to support the diagnosis of follicular cell lymphoma t(14;18),(q32;q21), mantle cell lymphoma t(11;14)(q13;q32), and Burkitt's lymphoma t(2;8),t(8;14) and t(8;22). T-Cell lymphomas may show changes in 14q11,7p or 7q. Many of the lymphomas are characterized by complex karyotypic changes. Specific FISH probes are useful in determining characteristic or identifying marker chromosomes. Cytogenetic and FISH studies aid in the diagnosis, correct classification, and evaluation of therapy for a variety of lymphomas.

Acute myelomonocytic leukemia with histologic features resembling sarcomatoid carcinoma in bone marrow.

We report a case of primary acute myelomonocytic leukemia involving the bone marrow that resembled sarcomatoid carcinoma. The neoplastic cells in bone marrow biopsy specimens formed cohesive-appearing clusters and cords separated by an immature fibroblastic proliferation and myxoid stroma. Blasts in the bone marrow aspirate smears formed clusters and sheets, and a subset of blasts exhibited erythrophagocytosis. Dysgranulopoiesis was also present. Lineage was confirmed by immunohistochemical analysis of formalin-fixed, paraffin-embedded tissue. The tumor cells showed strong reactivity for lysozyme, myeloperoxidase, CD45, and CD68 and were negative for keratin, S100, CD20, and CD3. The serum lysozyme concentration (110 microgram/mL) was 13 times greater than the normal value (8 microgram/mL). Cytogenetic studies performed on bone marrow aspirate material revealed a complex karyotype, including trisomy 8 and abnormalities of chromosome 11q. We report this case of acute myelomonocytic leukemia because the neoplastic cells appeared cohesive and spindled, resembling sarcomatoid carcinoma, and therefore caused diagnostic difficulty. Other monocytic neoplasms with similar resemblance to carcinoma or sarcoma have been reported in the literature, suggesting that the tendency to appear cohesive may be an inherent characteristic of neoplastic cells with monocytic differentiation.

Cytogenetics, in situ hybridization and molecular approaches in the diagnosis of cancer.

The past 100 years represent almost the entire history of the recognition of the role of genetics in human cancer. The purpose of this work is to: 1) review that history; 2) explore the techniques that have brought cancer genetics to its present state of knowledge; and 3) to provide preliminary data on how cytogenetics, fluorescence in situ-hybridization (FISH) and molecular techniques contribute to the diagnosis of chronic myelogenous leukemia (CML). Conventional cytogenetics provided the first chromosomal marker for malignancy in 1960. This was to be known as the so-called Philadelphia chromosome. Additional chromosomal changes associated with various hematologic malignancies followed in the 1970s after chromosomal banding was perfected. FISH, polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR) and other molecular techniques followed. Using these techniques, the diagnosis and prognosis of CML continue to evolve. The current study evaluates 21 patients by conventional cytogenetics and compares the percentage of t(9;22) metaphases with FISH information on the bone marrow and peripheral blood specimens of the same patients. The correlation of the techniques in this small study is 100 percent. Depending on the cutoff for abnormal FISH, 10 percent or less of the FISH studies on bone marrow or peripheral blood are false negatives. Conventional cytogenetics is used as the present gold standard. FISH and molecular techniques are complementary and will provide additional significant information in the future.

Nationwide survey of home transfusion practices.

BACKGROUND: Limited information exists on home transfusion practices. STUDY DESIGN AND METHODS: In 1995, a survey requesting data for 1994 was sent to 1273 American Association of Blood Banks (AABB) institutional members and 113 non-AABB home health care agencies that provide out-of-hospital transfusions. RESULTS: Of 943 respondents, 102 provide blood to a home transfusion program, 37 provide blood and run a home transfusion program, and 13 run a home transfusion program only, for a total of 152 (16%) with some involvement in home blood transfusions. Most of the 50 respondents with a home transfusion program are licensed by their state and accredited by the Joint Commission on Accreditation of Healthcare Organizations. All respondents have written policies for home transfusion, and 90 percent require a signed informed-consent document before initiating transfusions in the home. Most have policies requiring that there be a second adult and a telephone in the home, that the home be deemed safe for transfusion, that the patient's physician be readily available, and that the patient have had prior transfusions. The most common component issued by the blood providers was red cells, followed by platelets. White cell-reduced components were always provided by 36 percent of respondents. The most common patient diagnosis was cancer. Home transfusions were provided primarily by registered nurses. Only 14 percent of respondents indicated that the medical director of the blood bank is responsible for approving a patient for home transfusion. A posttransfusion visit is performed by 46 percent of respondents. CONCLUSION: Although most facilities have policies for the administration of home transfusions, there remains marked heterogeneity among blood providers and transfusionists regarding home transfusion practices.

Chromosome 6 abnormalities associated with prolymphocytic acceleration in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is most characteristically associated with the cytogenetic abnormalities +12, 13q14, and 14q32. Recently abnormalities of chromosome 6 have been reported in patients with mantle zone lymphoma, CLL mixed type, and a CLL variant with larger prolymphocytoid cells in the peripheral blood. The purpose of this study was to review the cases of CLL karyotyped at the University of Texas M. D. Anderson Cancer Center (UTMDACC) and to determine the number and type of chromosome 6 abnormalities. Precisely 830 cases of CLL with karyotypes were reviewed. Among these, 257/830 (31 percent) had abnormal karyotypes, 56/257 (22 percent) had an abnormality of 6, 18/56 (32 percent) had translocations involving 6 and, in most instances, a different chromosome was involved, 37/56 (66 percent) had deletion 6 or loss of at least a portion of 6q, and 9/56 (16 percent) had an abnormality of 6p. The losses of 6q were in the q13 to q25 regions. Of these, 13/56 (23.2 percent) of patients with 6q abnormalities had > or = 10 percent prolymphocytes (PL) in the bone marrow (BM) and/or peripheral blood (PB), 10/56 (17.9 percent) had > or = 10 percent PL in the bone marrow, 8/56 (14.3 percent) had > or = 10 percent PL in the peripheral blood, and 5/56 (9 percent) had > or = 10 percent PL in both (see table I). The 201 CLL patients with chromosome abnormalities other than 6 contained 23 with excess PL (11.9 percent). A subset of karyotypic changes of 6 associated with increased PL is recognizable and may be useful in aiding in clinical diagnosis and therapy.

Interphase fluorescence in situ hybridization analysis: a study using centromeric probes 7, 8, and 12.

Interphase fluorescence in situ hybridization (I-FISH) is a useful technique for detecting chromosomal numerical abnormalities in tumors and is gaining acceptance as a tool in cytogenetics and clinical diagnoses. Performance and quality control information about commercial products are necessary in order to implement an individual FISH probe as a routine clinical laboratory test. Interphase FISH analysis was performed with three commercially available alpha-satellite chromosome-specific DNA centromeric probes (D7Z1/D7Z2; D8Z2; and D12Z3) on bone marrow material prepared for conventional cytogenetic analysis. The results were interpreted following enumeration of the signals in 500 interphase nuclei each by two different observers. A mean of 93.92 percent (+/- 1.3 percent, 1 SD) was found for chromosome 7; a mean of 93.91 percent (+/- 1.5 percent, 1 SD) was found for chromosome 8, and a mean of 92.85 percent (+/- 1.4 percent, 1 SD) was found for chromosome 12. The results of the study demonstrated that I-FISH using chromosome centromeric probe(s) is a reliable, reproducible, and accurate technique. This technique can be integrated into routine clinical practice with proper quality control protocols.

Applicability of direct in situ reverse transcription-polymerase chain reaction on bone marrow smears.

In situ reverse transcription (RT)-polymerase chain reaction (PCR) is a promising laboratory tool for biomedical investigation at the molecular level in tissues. Direct in-cell amplification of the breakpoint cluster region (BCR)-Abelson (ABL) fusion transcript of chronic myeloid leukemia (CML) has recently been accomplished in Italy using bone marrow mononuclear cell suspensions. The goals of this study are to determine if in situ RT-PCR amplification is possible on bone marrow spirate smears and to demonstrate any unique factors in this procedure. A commercially available method was used because of the existence of published protocols for adaptation. Bone marrow (BM) aspirate smears (n = 17) from patients with CML in blast crisis (positive case material) or other hematological malignancies (negative case material) were evaluated. Satisfactory amplification of the BCR-ABL fusion transcript occurred, and distinct blue cytoplasmic granules that varied in intensity were found in most CML blasts. The negative case materials lacked the specifically amplified granular signals. Overall signal strength and backgrounds were readily affected by the quality of the specimen as well as by changes in assay parameters. In conclusion, the direct in situ RT-PCR technique is applicable for bone marrow aspirate smear evaluation. However, it remains an investigative tool until optimization for sensitivity, specificity, and accuracy can be achieved.

Prognostic factors for survival of patients treated systemically for disseminated melanoma.

PURPOSE: The current American Joint Commission on Cancer (AJCC) staging system distinguishes between soft tissue and visceral metastases in advanced (stage IV) melanoma. We sought to verify these staging criteria and to identify prognostic variables that could be used to evaluate the impact of systemic therapy on long-term survival during the prior decade. PATIENTS AND METHODS: We conducted a retrospective study of patients with advanced cutaneous melanoma enrolled in clinical trials between 1979 and 1989 at The University of Texas M.D. Anderson Cancer Center. Pretreatment age, sex, number of organs with metastases, serum levels of lactate dehydrogenase (LDH) and albumin, and period of enrollment were analyzed using a Cox proportional hazards model of survival. RESULTS: In univariate and multivariate analyses that involved 318 stage IV patients, normal serum levels of LDH and albumin, soft tissue and/or single visceral organ metastases (especially lung), female sex, and enrollment late in the decade were independent positive predictors for survival. In multivariate analyses, the current AJCC criteria did not significantly predict outcome. Systemic treatment response did not bias these results, and only 4% of patients had a complete response. Patients who lived more than 2 years (11%) had a mix of favorable prognostic characteristics and a high frequency of systemic or surgically induced complete response. CONCLUSION: This study supports the use of stratification parameters that reflect the favorable prognostic impact of soft tissue or single visceral organ metastases and normal serum levels of LDH and albumin at time of enrollment in advanced melanoma trials. Improved survival over the prior decade probably reflects advances in diagnostic and palliative interventions.

Stable overexpression of PML alters regulation of cell cycle progression in HeLa cells.

Our previous studies demonstrated that PML is a growth suppressor that suppresses oncogenic transformation of NIH/3T3 cells and rat embryo fibroblasts. PML is a nuclear matrix-associated phosphoprotein whose expression is regulated during the cell cycle. Disruption of PML function by t(15;17) in acute promyelocytic leukemia (APL) plays a critical role in leukemogenesis. To further study the role of PML in the control of cell growth, we have stably overexpressed PML protein in the HeLa cell line. This overexpression of PML significantly reduced the growth rate of HeLa cells and suppressed anchorage-independent growth in soft agar. We consequently investigated several parameters correlated with cell growth and cell cycle progression. We found that, in comparison with the parental HeLa cells, HeLa/PML stable clones showed proportionally more cells in G1 phase, fewer cells in S phase and about the same number in G2/M phase. The HeLa/PML clones showed a significantly longer doubling time as a result of a lengthening of the G1 phase. No effect on apoptosis was found in HeLa cells overexpressing PML. This observation indicates that PML suppresses cell growth by increasing cell cycle duration as a result of G1 elongation. To further understand the mechanism of the effect of PML on HeLa cells, expression of cell cycle-related proteins in HeLa/PML and parental HeLa cells was analyzed. We found that Rb phosphorylation was significantly reduced in PML stable clones. Expression of cyclin E, Cdk2 and p27 proteins was also significantly reduced. These studies indicate that PML affects cell cycle progression by mediating expression of several key proteins that normally control cell cycle progression. These results further extend our current understanding of PML function in human cells and its important role in cell cycle regulation.

Fludarabine triphosphate inhibits nucleotide excision repair of cisplatin-induced DNA adducts in vitro.

Fludarabine (9-beta-arabinofuranosyl-2-fluoroadenine-5'-monophosphate) is clinically active against chronic lymphocytic leukemia and low-grade lymphomas. We reported previously that fludarabine nucleoside synergistically enhanced cisplatin (CDDP)-induced cytotoxicity in vitro, and that the synergism was concomitant with inhibition of removal of cellular CDDP-induced DNA interstrand cross-links, which are presumably repaired by homologous recombinational repair. To extend our work, we investigated whether fludarabine inhibits nucleotide excision repair (NER) of CDDP-induced DNA intrastrand adducts. The effect of fludarabine on NER was determined using a cell-free system in which a plasmid containing the DNA adducts served as the substrate for repair enzymes in whole-cell extracts from repair-competent cells. To prevent the cell-bound high mobility group box-containing proteins from interfering with repair, cell extracts were depleted with high mobility group box proteins by immunoprecipitation prior to the assay. Repair synthesis, measured by the incorporation of [(32)P]dATP or [(32)P]dCTP, was inhibited by 50% at 26 or 43 microM fludarabine triphosphate, respectively; the effect was dose dependent and may have resulted from the termination of repair-patch elongation. These results were consistent with those from pulse-chase experiments demonstrating the conversion of nicked circular plasmid to the closed circular form by cell extracts filling the repair gaps. When proliferating cell nuclear antigen-depleted cell extracts were used and aphidicolin was added in the repair assay to arrest NER at the incision/excision stage, 100 microM fludarabine triphosphate inhibited about 55% of the conversion of nicked plasmids from the closed circular damaged plasmid substrate; the inhibition was dose dependent. We conclude that fludarabine triphosphate inhibited NER at the steps of incision and repair synthesis. These results suggest that fludarabine may serve as a potential repair modulator to improve the antitumor efficacies of combination regimens containing agents that induce NER.

Downregulation of RAR alpha in mice by antisense transgene leads to a compensatory increase in RAR beta and RAR gamma and development of lymphoma.

Retinoic acid receptors (RARs) alpha, beta, and gamma contain retinoic acid response elements (RAREs) in their promoter regions and respond to their own activation, thus forming an autoregulatory loop. We generated transgenic mice that expressed an antisense construct of the RAR alpha. Homozygous transgenic mice demonstrated 30% to 80% reduction in RAR alpha protein expression in various tissues. Unlike RAR alpha null mice generated by knockout, our antisense mice demonstrated significant compensatory increases in the expression of RAR beta and RAR gamma proteins. Coarse fur, male sterility, and low body weight were other abnormalities observed in these mice. Most importantly, lymphoma developed in 44% of our homozygous transgenic mice at an early stage of life. These data suggest that RAR alpha is necessary for appropriate response of the RAR beta and RAR gamma genes to physiologic changes and deregulation of the RAR alpha in transgenic mice, which resulted in upregulation of RAR beta and RAR gamma, can be associated with lymphomagenesis. Thus, the data support the hypothesis that a balance among the RARs is necessary for appropriate response to various homeostatic needs.

Cytogenetics. An evolving role in the diagnosis and treatment of cancer.

Conventional cytogenetics has been used for many years in the diagnosis and follow-up of myeloproliferative disorders. Molecular techniques including FISH and gene rearrangements are complementary in the evaluation of myeloproliferative and myelodysplastic disorders. Lymphomas and lymphocytic leukemias have nonrandom cytogenetic patterns that are useful in the clinical diagnosis, prognosis, and therapeutic follow-up. Solid tumors have complex karyotypic and genetic abnormalities, and clinical utilization of conventional cytogenetics and molecular techniques is in the developmental stages of applicability. The benefits of karyotype analysis in myeloproliferative and lymphoproliferative diseases include guidance for diagnostic and therapeutic approaches as well as assessment of minimal residual disease. Conventional cancer cytogenetics and commercially available FISH reagents enhance these applications. Molecular diagnostic techniques are analytically sensitive and specific. The complexities of the function and role of genetic abnormalities in solid tumors present challenges in the choice, interpretation, and application of conventional cytogenetic and molecular data. These challenges offer exciting potential for future advances.

Underestimation of monoclonal proteins by agarose serum protein electrophoresis.

The effect of serum dilution on monoclonal protein quantitation by serum protein electrophoresis (SPE) on the agarose gel Paragon system was investigated in 388 serum samples from 106 patients with Ig G monoclonal gammopathy. It was found that the pre-electrophoretic 1:5 serum dilution recommended by the manufacturer was adequate for some but not all sera, especially those with the highest M-protein concentrations. As a result of the inadequate dilution, 232 (60 percent) of the 388 samples had M-protein concentrations that were significantly underestimated and the corresponding albumin concentrations overestimated. By Paragon SPE, the mean albumin concentration in these 232 sera was 41.8 (SD 6.7) g/L. After further dilution of these sera, the mean albumin concentration was 36.7 (SD 6.8) g/L and was, in each case, always less than that in the corresponding 1:5 diluted serum. By the bromcresol green (BCG) dye-binding method, the albumin concentration was 34.9 (SD 4.3) g/L. Similarly, the M-protein concentration for 1:5 diluted sera was 51.9 (SD 12.9) g/L vs. 59.1 (SD 16.1) g/L for the further diluted sera, with the M-protein concentration in each further diluted sample always exceeding that in the corresponding 1:5 diluted serum. Underestimation of the M-protein concentration limits its clinical utilization in evaluating the patient's response to therapy and for early detection of disease progression. A recommendation was made of a 1:10 dilution of sera that contain total protein from 91 g/L to 114 g/L and a 1:20 dilution of sera in which the protein content is in the range of 115 g/L to 152 g/L to insure accurate estimation of protein fractions by Paragon SPE.