Lessons learned for spine SABR?

•SABR has shown survival benefits in oligometastatic cases, particularly in low-volume metastatic disease states.•Spine SABR offers potential improvements in local control, and pain response for metastatic spine tumors.•Technical requirements for SABR, like advanced image guidance and immobilization systems, are increasingly available.•Current data suggests high local control rates (75-95%) and variable pain responses (40-90%) with SABR using single or multi-fraction regimens.•Further randomized trials are needed to explore SABR applications in different scenarios and populations, while considering global health aspects for wider accessibility.

Optimizing Clinical Implementation of Hypofractionation: Comprehensive Evidence Synthesis and Practical Guidelines for Low- and Middle-Income Settings

The global cancer burden, especially in low- and middle-income countries (LMICs), worsens existing disparities, amplified by the rising costs of advanced treatments. The shortage of radiation therapy (RT) services is a significant issue in LMICs. Extended conventional treatment regimens pose significant challenges, especially in resource-limited settings. Hypofractionated radiotherapy (HRT) and ultra-hypofractionated/stereotactic body radiation therapy (SBRT) offer promising alternatives by shortening treatment durations. This approach optimizes the utilization of radiotherapy machines, making them more effective in meeting the growing demand for cancer care. Adopting HRT/SBRT holds significant potential, especially in LMICs. This review provides the latest clinical evidence and guideline recommendations for the application of HRT/SBRT in the treatment of breast, prostate, and lung cancers. It emphasizes the critical importance of rigorous training, technology, stringent quality assurance, and safety protocols to ensure precise and secure treatments. Additionally, it addresses practical considerations for implementing these treatments in LMICs, highlighting the need for comprehensive support and collaboration to enhance patient access to advanced cancer care.

Analysis of multicatheter interstitial brachytherapy: Accelerated partial breast irradiation in a retrospective cohort of early-stage breast cancer patients

PURPOSE

To determine cardiac dose received by patients treated with high dose rate interstitial brachytherapy. Patients with early-stage, node negative breast cancer can be treated using multi-catheter interstitial brachytherapy accelerated partial breast irradiation (MIB-APBI), with the benefit of reduced treatment volumes and favorable toxicity.

METHODS AND MATERIALS

We conducted a retrospective review of left-sided breast cancer patients treated using MIB-APBI at our institution since 2014. The mean heart dose (MHD) was calculated using the Oncentra 3.2 planning system. The minimum distance between the planning target volume (PTVeval) and heart contour was measured manually.

FINDINGS

81 patients were included. The upper outer quadrant was the most common site. The MHD was 97.8 cGy (EQD2a/b=2) (range 22-229 cGy). MHD significantly correlated with the closest distance between PTVeval and heart contour (correlation coefficient -0.823, p <0.001); size of PTVeval (cc) and quadrant location did not.

CONCLUSIONS

Appropriately selected women with early-stage, low-risk, left-sided breast cancer who received MIB-APBI had acceptable MHD. There was a strong correlation between the distance of PTVeval and MHD. Quadrant breast tumor is in cannot be used as a surrogate for MHD in brachytherapy. Our findings contribute to the growing evidence of the utility and safety of MIB-APBI.

Survival outcomes and predicting intracranial metastasis in stage III non-small cell lung cancer treated with definitive chemoradiation: Real-world data from a tertiary cancer center

PURPOSE/OBJECTIVE

Around 30% of patients with non-small cell lung cancers (NSCLC) are diagnosed with stage III disease at presentation, of which about 50% are treated with definitive chemoradiation (CRT). Around 65-80% of patients will eventually develop intracranial metastases (IM), though associated risk factors are not clearly described. We report survival outcomes and risk factors for development of IM in a cohort of patients with stage III NSCLC treated with CRT at a tertiary cancer center.

MATERIALS/METHODS

We identified 195 patients with stage III NSCLC treated with CRT from January 2010 to May 2021. Multivariable logistic regression was used to generate odds ratios for covariates associated with development of IM. Kaplan-Meier analysis with the Log Rank test was used for unadjusted time-to-event analyses. P-value for statistical significance was set at < 0.05 with a two-sided test.

RESULTS

Out of 195 patients, 108 (55.4%) had stage IIIA disease and 103 (52.8%) had adenocarcinoma histology. The median age and follow-up (in months) was 67 (IQR 60-74) and 21 (IQR 12-43), respectively. The dose of radiation was 60 Gy in 30 fractions for148 patients (75.9%). Of the 77 patients who received treatment since immunotherapy was available and standard at our cancer center, 45 (58.4%) received at least one cycle. During follow-up, 84 patients (43.1%) developed any metastasis, and 33 (16.9%) developed IM (either alone or with extracranial metastasis). 150 patients (76.9%) experienced a treatment delay (interval between diagnosis and treatment > 4 weeks). Factors associated with developing any metastasis included higher overall stage at diagnosis (p = 0.013) and higher prescribed dose (p = 0.022). Factors associated with developing IM included higher ratio of involved over sampled lymph nodes (p = 0.001) and receipt of pre-CRT systemic or radiotherapy for any reason (p = 0.034). On multivariate logistical regression, treatment delay (OR 3.9, p = 0.036) and overall stage at diagnosis (IIIA vs. IIIB/IIIC) (OR 2.8, p = 0.02) predicted development of IM. These findings were sustained on sensitivity analysis using different delay intervals. Median OS was not reached for the overall cohort, and was 43.1 months for patients with IM and 40.3 months in those with extracranial-only metastasis (p = 0.968). In patients with any metastasis, median OS was longer (p = 0.003) for those who experienced a treatment delay (48.4 months) compared to those that did not (12.2 months), likely due to expedited diagnosis and treatment in patients with a higher symptom burden secondary to more advanced disease.

CONCLUSIONS

In patients with stage III NSCLC treated with definitive CRT, the risk of IM appears to increase with overall stage at diagnosis and, importantly, may be associated with experiencing a treatment delay (> 4 weeks). Metastatic disease of any kind remains the primary life-limiting prognostic factor in these patients with advanced lung cancer. In patients with metastatic disease, treatment delay was associated with better survival. Patients who experience a treatment delay and those initially diagnosed at a more advanced overall stage may warrant more frequent surveillance for early diagnosis and treatment of IM. Healthcare system stakeholders should strive to mitigate treatment delay in patients with locally NSCLC to reduce the risk of IM. Further research is needed to better understand factors associated with survival, treatment delay, and the development of IM after CRT in the immunotherapy era.

A Precise Approach for Radiotherapy of Breast Cancer

Radiotherapy is an integral part of the multidisciplinary management of breast cancer (BC). There have been multiple recent advances in the delivery of radiotherapy, reviewed with a critical discussion of the evidence from trials investigating adjuvant ultra-hypofractionation and partial breast irradiation for early-stage BC, and the locoregional management of lymph nodes in locally advanced BC. Multiple precision medicine-based approaches have been developed as prognostic and/or predictive for BC patients and identifying biomarkers of radioresistance could help identify patients that may benefit from dose-escalated radiotherapy or radiosensitizers. Radiotherapy after breast reconstruction is an area of current controversy in the field, and we evaluated the decision-making considerations in this situation. The oligometastatic state is an emerging field for many cancer sites based on recent trials investigating ablative radiotherapy for oligometastatic BC. This chapter is an overview of radiotherapy for BC, with a focus on recent advances in early-stage, locally advanced, and oligometastatic disease.

Mortality due to cancer treatment delay: systematic review and meta-analysis

OBJECTIVE

To quantify the association of cancer treatment delay and mortality for each four week increase in delay to inform cancer treatment pathways.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Published studies in Medline from 1 January 2000 to 10 April 2020.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Curative, neoadjuvant, and adjuvant indications for surgery, systemic treatment, or radiotherapy for cancers of the bladder, breast, colon, rectum, lung, cervix, and head and neck were included. The main outcome measure was the hazard ratio for overall survival for each four week delay for each indication. Delay was measured from diagnosis to first treatment, or from the completion of one treatment to the start of the next. The primary analysis only included high validity studies controlling for major prognostic factors. Hazard ratios were assumed to be log linear in relation to overall survival and were converted to an effect for each four week delay. Pooled effects were estimated using DerSimonian and Laird random effect models.

RESULTS

The review included 34 studies for 17 indications (n=1 272 681 patients). No high validity data were found for five of the radiotherapy indications or for cervical cancer surgery. The association between delay and increased mortality was significant (P<0.05) for 13 of 17 indications. Surgery findings were consistent, with a mortality risk for each four week delay of 1.06-1.08 (eg, colectomy 1.06, 95% confidence interval 1.01 to 1.12; breast surgery 1.08, 1.03 to 1.13). Estimates for systemic treatment varied (hazard ratio range 1.01-1.28). Radiotherapy estimates were for radical radiotherapy for head and neck cancer (hazard ratio 1.09, 95% confidence interval 1.05 to 1.14), adjuvant radiotherapy after breast conserving surgery (0.98, 0.88 to 1.09), and cervix cancer adjuvant radiotherapy (1.23, 1.00 to 1.50). A sensitivity analysis of studies that had been excluded because of lack of information on comorbidities or functional status did not change the findings.

CONCLUSIONS

Cancer treatment delay is a problem in health systems worldwide. The impact of delay on mortality can now be quantified for prioritisation and modelling. Even a four week delay of cancer treatment is associated with increased mortality across surgical, systemic treatment, and radiotherapy indications for seven cancers. Policies focused on minimising system level delays to cancer treatment initiation could improve population level survival outcomes.

The Oncotype Dx Assay in ER-Positive, HER2-Negative Breast Cancer Patients: A Real Life Experience from a Single Cancer Center

Objective

To determine the influence of the Oncotype Dx assay on the treatment of patients with Estrogen Receptor (ER)-positive, Human Epidermal Growth Factor Receptor 2 (HER2)-negative, axillary lymph node-negative or micrometastatic carcinoma of the breast in a single cancer center. In addition, patients with intermediate Oncotype Dx recurrence scores were analyzed to assess the factors influencing therapeutic decisions for adjuvant chemotherapy.

Materials and Methods

Data from medical records of women diagnosed with carcinoma of the breast and qualified for the Oncotype Dx assay were extracted (OncoDx cohort). Patient demographic and cancer characteristics, genomic report, and course of treatment data, including survival outcomes and treatment decision-making, were analyzed. A matched cohort of patients with similar tumor stage and biology (ER-positive, HER2-negative) from the era before the introduction of the Oncotype Dx assay was analyzed for comparison (pre-OncoDx cohort).

Results

Two hundred and one patients were included in the OncoDx cohort and one hundred and sixty patients were included in the pre-OncoDx cohort. Oncotype Dx recurrence score (RS) was low (<11) in fifty-six patients (28%), intermediate (11-25) in one hundred and twenty-three patients (61.5%) and high (>25) in twenty one patients (10.5%). Demographic and cancer clinicopathologic characteristics between OncoDx and pre-OncoDx cohorts were similar. Overall, 10.9% of the patients in the OncoDx cohort received adjuvant chemotherapy, versus 23.8% of the patients in the pre-OncoDx cohort (Fisher exact p=0.003). Fewer patients were recommended adjuvant chemotherapy in the OncoDx era compared to the pre-OncoDx era (17.9% vs 30.6%, respectively, Fisher exact p=0.006). The decision to recommend chemotherapy within the intermediate-risk cohort was influenced by the patient's RS. The mean RS of patients in the intermediate-risk cohort who did not receive chemotherapy was 21.5 while the score of those that received chemotherapy was 24.6 (p=0.000). The series confirmed excellent PFS and OS for both OncoDx and pre-OncoDx cohorts.

Conclusion

This single cancer center analysis confirms the avoidance of chemotherapy in the great majority of patients with early ER-positive, HER2-negative, lymph node-negative or micrometastatic carcinoma of the breast since the introduction of the Oncotype Dx assay. A higher recurrence risk score within the intermediate group may influence the decision for chemotherapy inclusion in the adjuvant treatment plan. A lower PR percentage by IHC and higher grade may predict higher Oncotype Dx scores.

De-indexed estimated glomerular filtration rates: A simple step towards improving accuracy of drug dosing of renally excreted medications in moderate to severe obesity

Kidney function is underestimated in obese individuals when standard equations are applied. Laboratory-reported estimated glomerular filtration rates (eGFR) report glomerular filtration rates corrected for body surface area in mL/min per 1.73 m² using modification of diet in renal disease or the chronic kidney disease-Epidemiology Collaboration equations. This may result in premature discontinuation or reduction in dosage of renally excreted medications. Currently, there are no clinical guidelines defining thresholds beyond which physicians should consider de-indexing patient eGFR values. We compared standard and de-indexed eGFR values for 281 consecutive patients seen in our chronic kidney disease clinic. In our study, half of the patients with a body mass index above 35 had clinically significant changes in their eGFR, with an improvement in chronic kidney disease stage, when eGFR was de-indexed. We propose that eGFR de-indexing should be considered in patients with moderate to severe obesity when calculating the dose, especially for medications that are excreted by the kidneys.

Abstract P2-07-11: Prediction of the Oncotype Dx recurrence score (RS) from clinicopathologic factors

Background: The Oncotype Dx assay is currently used as an aid to therapeutic decisions for the adjuvant treatment of women with ER-positive, Her2-negative, lymph node-negative or -micrometastatic breast cancer. The recently reported TAILORx study showed that no or minimal benefit is derived from adjuvant chemotherapy in patients with an Oncotype Dx Recurrence Score (RS) of 25 or less.

Methods: Charts of breast cancer patients that had the Oncotype Dx test in our cancer center in a nine-year period were reviewed. Data on demographic, and cancer-specific characteristics of the included patients were extracted. Predicted disease recurrence from the Oncotype Dx test was recorded and correlated with select clinicopathologic characteristics.

Results: Two hundred and thirty patients with ER-positive, Her2-negative, lymph node-negative or micrometastatic breast cancer were included. Mean age was 65 years-old (SD 9.9). Two hundred and three patients (88.3%) were post-menopausal and one hundred and thirty-three patients (57.8%) were 65 years-old or older. Two hundred and nine patients (90.9%) had lymph node-negative disease. Oncotype Dx recurrence score was low (&lt;11) in sixty-four patients (27.8%), intermediate (11-25) in one hundred and forty patients (60.9%) and high (&gt;25) in twenty-six patients (11.3%). High tumor grade and low progesterone receptor (PR) staining by IHC were the two clinicopathologic factors most associated with a high Oncotype Dx RS (x2 test p &lt;0.00001 and Fisher's exact test p &lt;0.0001). A predictive index (PI) was constructed, assigning one point each for grade 3 and PR staining in 20% or less of tumor cells. A PI of 0 was observed in one hundred and thirty-eight patients (60%), a PI of 1 was observed in seventy-one patients (30.9%), and a PI of 2 was observed in twenty-one patients (9.1%). One hundred and thirty-four patients (97.1%) with a PI of 0 had a RS of 25 or less. Patients with a PI of 1 and 2 had a RS of &gt;25 in 12.7% and 61.9% of cases, respectively.

Conclusion: The PI based on tumor grade and PR we propose is a simple predictor of Oncotype Dx RS. 97.1% of patients with a grade 1 or 2 tumor and PR positivity in &gt;20% of tumor cells had a RS of 25 or less. The Oncotype Dx test and its associated cost can therefore be avoided in these patients, especially in low-resource settings.

Citation Format: Voutsadakis IA, Thibodeau S, Reed M. Prediction of the Oncotype Dx recurrence score (RS) from clinicopathologic factors [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-07-11.

FOLFIRINOX Chemotherapy in Metastatic Pancreatic Cancer: A Systematic Review and Meta-Analysis of Retrospective and Phase II Studies

The introduction of the FOLFIRINOX regimen within the last decade marked the first progress in the clinical field of metastatic pancreatic cancer which had not seen any improvements in treatment availability for several years. In a phase III randomized clinical trial, FOLFIRINOX showed superior efficacy compared to the previous standard treatment of gemcitabine monotherapy. Nevertheless, it is unknown whether the superior results observed in this single phase III clinical trial can be translated more broadly to clinical practice. Our investigation sought to analyze all published evidence of the FOLFIRINOX regimen in series and phase II trials and compare it to the experience of the phase III study. Survival analysis revealed that FOLFIRINOX was associated with an Overall Survival of 10–11 months both in the trials and in off-trial settings, with response rates also similar in both settings. The adverse effect profile was consistent between the pooled phase II and off-trial experience and the FOLFIRINOX regimen arm observed in the randomized phase III trial.

Interlaboratory assay reproducibility study for loss of heterozygosity on chromosome 18 (18q LOH) in colon cancer

4052

Background: 18q LOH may be a useful marker in stage II colon carcinoma to assess who needs adjuvant chemotherapy. The objective of this study was to evaluate the intra- and inter-laboratory reproducibility of an assay for 18q LOH that is similar to the integral assay used in E5202, the current Intergroup phase III stage II colon carcinoma clinical trial. Methods: Specimens from 130 stage II/III colon cancer patients were obtained from the Cooperative Human Tissue Network and evaluated at three different laboratories. Samples were divided into subsamples, coded and distributed. Each laboratory used similar equipment in an established PCR protocol with 5 dinucleotide repeats. Starting materials used both histologic sections and extracted DNA samples of tumor and non-neoplastic tissue obtained only by scalpel microdissection. LOH was defined as tumor/normal peak ratio that was >1.35 or <0.67 without microsatellite instability (MSI). Tumors were categorized as either MSI+, LOH + or -, uninformative/monoallelic, or unevaluable (DNA not amplifiable). Standard tests assessed reproducibility of both the numerical ratios and the tumor 18q LOH status. Results: Sample quality issues prevented analysis of 13 tumors (10%). The frequency of 18q LOH was 64%. The probability of agreement on the same tumor evaluated twice was 92% (Cohen's kappa 0.83). Intra-class correlation coefficients for individual markers were consistently over 0.90. Tissue specimens must have high (>85%) tumor cell content for reproducibility. Differences among patients affected reproducibility much more than effects of laboratory and sample type (DNA vs. histologic section). Conclusions: This study validates reproducibility of the 18q LOH assay for both clinical categorization of status and numerical ratios if samples are high quality and appropriate for scalpel microdissection.

[Table: see text]

[Rectal carcinomas in HNPCC]

The true incidence of rectal cancer in HNPCC is still unknown. In our retrospective series analyzing 42 probands from HNPCC families, we found rectal cancer primaries in 29% of our probands. Patients with a first cancer diagnosed in the rectum developed metachronous colon cancer in 54% of the cases. These numbers indicate a requirement to discuss the most appropriate surgical procedure for preventive intervention (ileorectal anastomosis versus ileoanal pouch procedure).

Evidence for a prostate cancer susceptibility locus on the X chromosome

Over 200,000 new prostate cancer cases are diagnosed in the United States each year, accounting for more than 35% of all cancer cases affecting men, and resulting in 40,000 deaths annually. Attempts to characterize genes predisposing to prostate cancer have been hampered by a high phenocopy rate, the late age of onset of the disease and, in the absence of distinguishing clinical features, the inability to stratify patients into subgroups relative to suspected genetic locus heterogeneity. We previously performed a genome-wide search for hereditary prostate cancer (HPC) genes, finding evidence of a prostate cancer susceptibility locus on chromosome 1 (termed HPC1; ref. 2). Here we present evidence for the location of a second prostate cancer susceptibility gene, which by heterogeneity estimates accounts for approximately 16% of HPC cases. This HPC locus resides on the X chromosome (Xq27-28), a finding consistent with results of previous population-based studies suggesting an X-linked mode of HPC inheritance. Linkage to Xq27-28 was observed in a combined study population of 360 prostate cancer families collected at four independent sites in North America, Finland and Sweden. A maximum two-point lod score of 4.60 was observed at DXS1113, theta=0.26, in the combined data set. Parametric multipoint and non-parametric analyses provided results consistent with the two-point analysis. Significant evidence for genetic locus heterogeneity was observed, with similar estimates of the proportion of linked families in each separate family collection. Genetic mapping of the locus represents an important initial step in the identification of an X-linked gene implicated in the aetiology of HPC.

Different mechanisms underlie DNA instability in Huntington disease and colorectal cancer

Two recent lines of evidence raise the possibility that instability in germ-line or somatic cells arises by a common mechanism that involves defective mismatch repair. Mutations in mismatch-repair proteins are known to cause instability in hereditary nonpolyposis colorectal cancer, instability that is physically similar to germ-line instability observed in Huntington disease (HD). Furthermore, both germ-line and somatic-cell instability are likely to be mitotic defects, the former occurring early in embryogenesis. To test the hypothesis that defective repair is a common prerequisite for instability, we have utilized two disease groups that represent different instability "conditions." Germ-line instability within simple tandem repeats (STR) at 10 loci in 29 HD families were compared with somatic instability at the same loci in 26 colon cancer (CC) patients with identified or suspected defects in mismatch-repair enzymes. HD is known to be caused by expansion within the CAG repeat of the locus, but the extent or pattern of STR instability outside this region has not been examined systematically. We find a distinctly different pattern of STR mutation in the two disease groups, suggesting different mechanisms. Instability in HD is generally confined to a single locus, whereas instability is widespread for the same loci in CC. Our data do not support a causative role for defective mismatch-repair enzymes in instability associated with HD; rather, our data are consistent with a model in which DNA structure may inhibit normal mismatch repair at the expansion site.

Segregation of the fragile X mutation from a male with a full mutation: unusual somatic instability in the FMR-1 locus

Fragile X syndrome is associated with an unstable CGG-repeat in the FMR-1 gene. There are few reports of affected males transmitting the FMR-1 gene to offspring. We report on a family in which the propositus and his twin sister each had a full mutation with abnormal methylation. Their mother had an FMR-1 allele in the normal range and a large premutation, with normal methylation. The maternal grandmother had two normal FMR-1 alleles. The maternal grandfather had an unusual somatic FMR-1 pattern, with allele size ranging from premutation to full mutation. No allele was detectable by PCR analysis. Multiple Southern blot analyses identified a hybridization pattern that originated at a distinct premutation band and extended into the full mutation range. Methylation studies revealed a mosaic pattern with both unmethylated premutations and methylated full mutations. This individual declined formal evaluation but did not finish high school and has difficulty in reading and writing. The size of the premutation FMR-1 allele passed to his daughter is larger than his most prominent premutation allele. This is most likely due to gonadal mosaicism similar to that in his peripheral lymphocytes. Alternatively, this expansion event may have occurred during his daughter's early embryonic development and this large premutation allele is mitotically unstable. This pattern of FMR-1 alleles in a presumably mildly affected male is highly unusual. These findings are consistent with the absence of transmission of a full fragile X mutation through an expressing male. Studies of tissue specific FMR-1 allele expansion and FMR-1 protein expression on this individual should help to determine the correlation of the molecular findings with the phenotypic effects.

A study of aqueous humor formation in patients with cystic fibrosis

The circadian pattern of aqueous formation and the effect of timolol on aqueous flow was studied in 12 patients with cystic fibrosis. Cystic fibrosis is a disease characterized by a defect in a chloride channel-associated regulatory protein found in epithelial cells. Improper regulation of these chloride channels, causes abnormal composition of exocrine secretions, including respiratory tract, gastrointestinal tract, exocrine pancreas, and sweat glands. Ocular findings previously reported include abnormal endothelial cell permeability, decreased tear secretion, and abnormal tear composition. In this study, aqueous humor flow was measured by fluorophotometry. No statistically significant difference was found when flow rates measured during the morning, during the afternoon, at night, and after topical timolol treatment were compared to normal values. The conclusion is that the beta adrenergically regulated chloride selective channels defective in patients in cystic fibrosis do not play a major role in the formation of aqueous humor or they are not regulated by the cystic fibrosis transmembrane conductance regulator (CFTR).

Third-party-mediated graft rejection and graft-versus-host disease after T-cell-depleted bone marrow transplantation, as demonstrated by hypervariable DNA probes and HLA-DR polymorphism

Graft rejection after marrow transplantation is generally thought to be mediated by alloreactive immune effector cells of host origin. Transfused blood products also contain immune cells capable of alloreactivity against both donor graft and host. To reduce the risk of transfusion-associated graft-versus-host disease (GVHD) and graft rejection, standard procedure is to irradiate all blood products with at least 1,500 rad before transfusion. We report a patient with chronic myelogenous leukemia who developed graft rejection and GVHD after receiving a T-cell-depleted transplant from a serologically HLA-A, B, DR/DQ matched and mixed lymphocyte culture (MLC) nonreactive unrelated donor. Cytogenetic analysis of marrow cells collected at the time of graft rejection revealed a PH1-negative female karyotype that was not consistent with donor cells. Use of specific minisatellite DNA probes (YNH 24, H-RAS, and 3' HVR) revealed the exclusive presence of third-party (neither donor nor recipient) restriction-fragment-length polymorphisms (RFLP) in both peripheral blood and marrow. Repeat RFLP analysis 3 days later showed persistence of this unique third-party banding pattern. DNA-based HLA-typing, using polymerase chain reaction (PCR) and oligonucleotide probe hybridization, also showed these cells to be derived from an individual whose HLA-DR type was distinct from donor and recipient. Together, these findings suggested the presence of a proliferating population of transfused cells possessing alloreactivity against both donor graft and host, despite prior irradiation of all blood products with 2,000 rad. Limiting dilution analysis to assess the frequency of irradiated lymphocytes able to respond to mitogen revealed an approximate 5- to 6-log reduction at 1,500 to 2,000 rad as compared with unirradiated controls. These data indicate that a small percentage of lymphocytes can survive irradiation at these doses and suggest that existing blood-product irradiation guidelines may require reassessment, especially in T-cell-depleted transplant recipients.

Neonatal hyperbilirubinemia at high altitude

A previous retrospective study showed an increased frequency of neonatal hyperbilirubinemia at high altitude in Colorado. In a prospective study we found that 39% of newborns at 3100 m altitude vs 16% at 1600 m exhibited hyperbilirubinemia, defined as a day 3 serum bilirubin level of 205 mumol/L or higher. Increased bilirubin production at 3100 m vs 1600 m was shown by increased levels of corrected carboxyhemoglobin. This finding was supported by increased erythropoietin and bilirubin values in cord blood and increased hematocrit values at day 3 among infants at 3100 m vs 1600 m. The sustained elevation in bilirubin for breast-fed vs formula-fed infants at 1600 m was observed for both feeding types at 3100 m. The findings suggested that there is a hematologic response to decreased oxygen availability at high altitude, resulting in increased bilirubin production accompanied by delayed bilirubin clearance.

An intronic region within the human factor VIII gene is duplicated within Xq28 and is homologous to the polymorphic locus DXS115 (767)

The genomic sequences recognized by the anonymous probe 767 (DXS115) are localized to two sites within Xq28. One site lies within intron 22 of the factor VIII gene (FBC). Physical mapping suggests that the second site lies within 1.2 megabases of the F8C gene. The RFLPs detected by 767 are located within the second site. Genetic data suggest that F8C and DXS115 are tightly linked (theta max = .04; Zmax = 8.30). Recombination events in meioses informative for DXS52 (St14), DXS115, and F8C suggest that DXS115 and F8C lie distal to DXS52.

The bcr gene in Philadelphia chromosome positive acute lymphoblastic leukemia

In chronic myelogenous leukemia (CML) and in a percentage of childhood and adult acute lymphoblastic leukemia (ALL) the Philadelphia (Ph') chromosome is present in the leukemic cells of patients. This chromosome is the result of a reciprocal translocation between chromosomes 9 and 22. In CML the break on chromosome 22 occurs within the major breakpoint cluster region (Mbcr) of the bcr gene. In this study, we report on the examination of DNAs from nine Ph'-chromosome positive ALL patients for rearrangements within the bcr gene using Southern blot analysis. Of nine patients having a karyotypically identifiable Ph'-chromosome, only five exhibited rearrangements of the bcr gene. This could indicate that in ALL, chromosome 22 sequences other than the bcr gene are involved in the Ph'-translocation. Within the group of Ph'-positive ALL patients having a bcr gene breakpoint, a correlation appears to exist between the age of the patient and the location of the breakpoint within the gene: all or the vast majority of pediatric patients analyzed to date do not have a Mbcr breakpoint as found in CML and in adult ALL.

Fragile X syndrome: linkage analysis in black and white populations

Eleven white families and 10 black families have been studied to detect racial differences in the linkage of DNA markers flanking the fragile X site (FRAXA). The differences in the recombination fractions for F9-FRAXA and DX13-FRAXA were not significant. The pair St14-FRAXA exhibited no difference between the two groups. Although the sample size was small, it would appear that these DNA markers can be used in black persons for prenatal diagnosis and genetic counseling. A larger group of families would be necessary to determine if 4D8 and cX55.7 will be equally useful since these appear to have lower heterozygote frequencies in the black population.

Multilocus analysis of the fragile X syndrome

A multilocus analysis of the fragile X (fra(X] syndrome was conducted with 147 families. Two proximal loci, DXS51 and F9, and two distal loci, DXS52 and DXS15, were studied. Overall, the best multipoint distances were found to be DXS51-F9, 6.9%, F9-fra(X), 22.4%; fra(X)-DXS52, 12.7%; DXS52-DXS15, 2.2%. These distances can be used for multipoint mapping of new probes, carrier testing and counseling of fra(X) families. Consistent with several previous studies, the families as a whole showed genetic heterogeneity for linkage between F9 and fra(X).

Mapping of DNA markers close to the fragile site on the human X chromosome at Xq27.3

We report the identification of a new RFLP detected by the DNA probe MN12, which is linked to both the fragile site on the X chromosome at Xq27.3 and the highly polymorphic locus detected by St14 (DXS52). In situ mapping confirms the localisation of MN12 distal to the fragile site. A detailed physical analysis of this region of the X chromosome using pulsed-field gel electrophoresis has shown that MN12, St14 and DX13 (DXS15) are physically linked within a region of 470kb. A long range restriction map around the MN12 locus reveals at least two candidate HTF islands, suggesting the existence of expressed sequences in this region.

Optimized calcium/phosphorus solubility in a parenteral nutrition solution containing dicarboxylic amino acids and cysteine

The solubility of calcium and phosphorus was studied in neonatal parenteral nutrition solutions containing dicarboxylic amino acids and cysteine. Experimental amino acid solutions containing aspartic acid, glutamic acid, and cysteine in concentrations from 0.5% to 2.0% were studied with dextrose concentrations of 5-20% plus standard electrolyte, vitamin, and trace element additives. Solutions were held at room temperature for 24 hr prior to incubation in a 37 degrees C water bath for 30 min. The pH of each solution was determined. Precipitation was detected by light scattering on a Cobas Bio centrifugal analyzer. An absorbance greater than 0.015 at 600 nm was considered evidence of precipitation. The pH of test solutions ranged between 5.7 and 6.4. Increasing amino acid concentration produced an improvement in calcium/phosphate solubility. Change in dextrose concentration had a lesser effect. Solutions of 10% dextrose with 2% amino acids contained 40 mEq/liter calcium and 17 mmol/liter phosphorus without precipitation. Administered at 150 ml/kg/day, such a solution would provide 120 mg/kg body weight/day calcium and 80 mg/kg/day phosphorus, approximately the daily in utero accretion rates during the last trimester. This is not readily achieved in comparable solutions of previous amino acid formulations.