A retrospective cohort study of clinical value of PRL-3 in stage III human colorectal cancer.

ABSTRACT: The aim of this study was to investigate the expression of phosphatase of regenerating live-3 (PRL-3) in human stage III colorectal cancer (CRC) and to evaluate its correlation with metachronous liver metastasis (MLM) and prognosis.The retrospective cohort study included 116 stage III CRC primary tumors and 60 normal colorectal tissues. PRL-3 expression was measured by immunohistochemistry. We investigated the correlation of PRL-3 with clinicopathologic features by the chi-square test. The association of PRL-3 expression with MLM was assessed by binary logistic regression. Overall survival (OS) and disease-free survival (DFS) between patients with positive PRL-3 expression and those with negative PRL-3 expression were compared by the Kaplan-Meier method and Cox proportional hazards regression model.We found that 32.8% of stage III CRC primary tumors were PRL-3 positive, and 15.0% of normal colorectal epithelia showed high PRL-3 expression (P = .012). Seventeen tumors (47.2%) among 36 cases that developed MLM were PRL-3 positive, and only 21 tumors (26.3%) in the 80 cases that did not develop MLM had positive PRL-3 expression (P = .026). PRL-3 expression was associated with MLM (P = .028). Patients with positive expression of PRL-3 showed a significantly shorter OS (40.32 ±â€Š3.97 vs 53.96 ±â€Š2.77 months, P = .009) and DFS (34.97 ±â€Š4.30 vs 44.48 ±â€Š2.89 months, P = .036). A multivariate analysis indicated that PRL-3 expression was an independent unfavorable prognostic factor for OS (P = .007).Our study suggested that high PRL-3 expression is an independent risk factor for MLM and poor prognosis. PRL-3 is expected to be a promising biomarker for predicting the incidence of MLM and prognosis in patients with stage III CRC.

Genetic disruption of the small GTPase RAC1 prevents plexiform neurofibroma formation in mice with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a common cancer predisposition syndrome caused by mutations in the NF1 tumor suppressor gene. NF1 encodes neurofibromin, a GTPase-activating protein for RAS proto-oncogene GTPase (RAS). Plexiform neurofibromas are a hallmark of NF1 and result from loss of heterozygosity of NF1 in Schwann cells, leading to constitutively activated p21RAS. Given the inability to target p21RAS directly, here we performed an shRNA library screen of all human kinases and Rho-GTPases in a patient-derived NF1-/- Schwann cell line to identify novel therapeutic targets to disrupt PN formation and progression. Rho family members, including Rac family small GTPase 1 (RAC1), were identified as candidates. Corroborating these findings, we observed that shRNA-mediated knockdown of RAC1 reduces cell proliferation and phosphorylation of extracellular signal-regulated kinase (ERK) in NF1-/- Schwann cells. Genetically engineered Nf1flox/flox;PostnCre+ mice, which develop multiple PNs, also exhibited increased RAC1-GTP and phospho-ERK levels compared with Nf1flox/flox;PostnCre- littermates. Notably, mice in which both Nf1 and Rac1 loci were disrupted (Nf1flox/floxRac1flox/flox;PostnCre+) were completely free of tumors and had normal phospho-ERK activity compared with Nf1flox/flox ;PostnCre+ mice. We conclude that the RAC1-GTPase is a key downstream node of RAS and that genetic disruption of the Rac1 allele completely prevents PN tumor formation in vivo in mice.

Metachronous anaplastic sarcoma of the kidney and thyroid follicular carcinoma as manifestations of DICER1 abnormalities.

Anaplastic sarcoma of the kidney (ASK) is a tumor found in the pediatric age group and shows many histopathological similarities to pleuropulmonary blastoma (PPB). We present a 12-year-old girl diagnosed with ASK and, 3 years later, with thyroid follicular carcinoma (TFC) with DICER1 abnormalities. Germline insertion/deletion (p. G1809_S1814delinsA) and independent somatic mutations (p. E1705K in ASK, p. E1813D in TFC) were identified. All of these abnormalities are in the catalytic domain of RNase IIIb. Single-nucleotide polymorphism genotyping microarray revealed independent copy number alterations (trisomy 8, monosomy 10, loss of 17p, and partial gain of 17q in ASK; trisomy 5 and partial loss of Xq in TFC). The copy number alteration pattern of ASK was similar to the pattern previously reported in PPB. The present case implies that ASK is a renal counterpart of PPB and that ASK with DICER1 abnormalities should be suspected in a broader age group than PPB.

BRAF inhibitor therapy-associated melanocytic lesions lack the BRAF V600E mutation and show increased levels of cyclin D1 expression.

Newly appearing or changing melanocytic lesions (MLs) are a recently reported toxicity of BRAF inhibitor (BRAFi) therapy. Morphologically, MLs associated with BRAFi therapy (BRAFi-MLs) may demonstrate alarming features of melanoma with an epithelioid cell phenotype with notable cytologic atypia. We sought to characterize the clinicopathological and molecular features of BRAFi-MLs. A retrospective review over a 4-year period revealed 20 patients in which 44 MLs (including 11 control nevi) were characterized by histopathology, review of clinical medical records, and immunohistochemical (IHC) studies (with anti-BRAF V600E, anti-BAP1, anti-cyclin D1, and anti-p16); the percentage of IHC+ cells was scored. Of the 20 patients, 3 (15%) whose BRAFi-MLs were biopsied had a second primary cutaneous melanoma. Of the 44 BRAFi-MLs tested, 37 (100%) of 37 MLs available for BRAF V600E testing lacked expression in contrast to 1 (9%) of 11 control nevi (lesions not associated with targeted therapy). A significantly higher level of cyclin D1 expression (>50% IHC+ cells) was more commonly seen in BRAFi-MLs (44%) than in control nevi (9%). No difference in p16 expression in melanocytes was seen between the 2 groups. BRAF mutation status distinctly differs between BRAFi-MLs from melanomas and nevi biopsied in patients who do not receive BRAFi therapy. Morphologically, BRAFi-MLs demonstrate a greater degree of atypia than do control nevi. Furthermore, BRAFi-MLs with coexisting cutaneous keratinocyte toxicity developed during fewer days of targeted therapy. Paradoxical activation of the MAPK pathway in BRAF(WT) melanocytes may account for ~15% to 21% of patients developing a second new primary melanoma within a year of starting BRAFi therapy; thus, close clinical surveillance is warranted.

Identification of Unique, Heterozygous Germline Mutation, STK11 (p.F354L), in a Child with an Encapsulated Follicular Variant of Papillary Thyroid Carcinoma within Six Months of Completing Treatment for Neuroblastoma.

Papillary thyroid carcinoma (PTC) is rare in children, although it is a known secondary malignancy after treatment for neuroblastoma (NB). The interval between NB treatment completion and PTC is usually more than 5 years. A 4-year-old, female patient with a high risk adrenal NB was found to have a 2.9-cm, right thyroid nodule on surveillance chest computed tomography (CT) 6 months after completion of her NB treatment (induction chemotherapy, tumor resection, autologous stem cell transplantation, external beam radiation to the abdominal tumor site, immunotherapy, and retinoic acid). Posttreatment surveillance included iodine-123-metaiodobenzylguanidine scans and CT scans. Fine-needle aspiration of the thyroid nodule diagnosed a follicular neoplasm, which was negative for BRAF, NRAS, KRAS, HRAS, PAX8/PPARg, and RET/PTC mutations, without evidence of metastatic NB. Nodule histology demonstrated an encapsulated follicular variant of PTC (FVPTC). Next-generation sequence analysis for a 46 cancer-gene profile was performed on both tumors with subsequent peripheral blood DNA testing. A heterozygous missense mutation in STK11 (F354L) was identified in both the NB and FVPTC. This mutation was also detected in peripheral blood mononuclear cells. Two additional heterozygous somatic missense mutations of uncertain significance were identified: KDR/VEGF receptor 2 (Q472H) on chromosome 4 and MET (N375S) on chromosome 7. To our knowledge, this is the shortest reported duration from completion of NB treatment to detection of thyroid cancer. The association of the STK11 gene with Peutz-Jeghers syndrome, lung adenocarcinomas, and medullary thyroid cancer leads to a possible association between this genetic variant and our patient's tumors.

Second malignant neoplasms in patients with Cowden syndrome with underlying germline PTEN mutations.

PURPOSE: Patients with Cowden syndrome (CS) with underlying germline PTEN mutations are at increased risk of breast, thyroid, endometrial, and renal cancers. To our knowledge, risk of subsequent cancers in these patients has not been previously explored or quantified. PATIENTS AND METHODS: We conducted a 7-year multicenter prospective study (2005 to 2012) of patients with CS or CS-like disease, all of whom underwent comprehensive PTEN mutational analysis. Second malignant neoplasms (SMNs) were ascertained by medical records and confirmed by pathology reports. Standardized incidence ratios (SIRs) for all SMNs combined and for breast, thyroid, endometrial, and renal cancers were calculated. RESULTS: Of the 2,912 adult patients included in our analysis, 2,024 had an invasive cancer history. Germline pathogenic PTEN mutations (PTEN mutation positive) were identified in 114 patients (5.6%). Of these 114 patients, 46 (40%) had an SMN. Median age of SMN diagnosis was 50 years (range, 21 to 71 years). Median interval between primary cancer and SMN was 5 years (range, <1 to 35 years). Of the 51 PTEN mutation-positive patients who presented with primary breast cancer, 11 (22%) had a subsequent new primary breast cancer and 10-year second breast cancer cumulative risk of 29% (95% CI, 15.3 to 43.7). Risk of SMNs compared with that of the general population was significantly elevated for all cancers (SIR, 7.74; 95% CI, 5.84 to 10.07), specifically for breast (SIR, 8.92; 95% CI, 5.85 to 13.07), thyroid (SIR, 5.83; 95% CI, 3.01 to 10.18), and endometrial SMNs (SIR, 14.08.07; 95% CI, 7.10 to 27.21). CONCLUSION: Patients with CS with germline PTEN mutations are at higher risk for SMNs compared with the general population. Prophylactic mastectomy should be considered on an individual basis given the significant risk of subsequent breast cancer.

Histopathologic characteristics of therapy-associated cutaneous neoplasms with vemurafenib, a selective BRAF kinase inhibitor, used in the treatment of melanoma.

BACKGROUND: Activating mutations in BRAF have been observed in up to 60% of melanomas, indicating a pivotal role for kinase deregulation in tumor progression. Vemurafenib is a specific inhibitor of BRAF for treatment of melanomas with activating BRAF V600E mutations and has been a major advancement in melanoma treatment. Treatment with vemurafenib, and to a lesser extent, sorafenib, a relatively non-specific inhibitor of BRAF, has been associated with cutaneous squamous cell carcinoma (SCC). METHODS: Clinical and microscopic characteristics of cutaneous neoplasms were evaluated following vemurafenib administration. RESULTS: Twenty-four of 47 (51%) patients receiving vemurafenib at our institution developed 146 total cutaneous neoplasms, with 75% developing multiple lesions. The median number of lesions in affected patients was three. Body distribution included head/neck (29%), chest/back (21%), upper (23%) and lower extremities (27%). Lesions were biopsied and pathologically showed multiple types of epidermal tumors including, but not limited to, verrucous keratoses with/without partial thickness dysplasia, actinic keratoses and well-differentiated and invasive SCCs with/without keratoacanthomatous features. CONCLUSIONS: We describe the histopathologic findings of skin lesions potentially associated with vemurafenib. Additional investigation is necessary to further elucidate cutaneous neoplasms associated with vemurafenib; however, frequent dermatologic evaluation is warranted in all patients receiving BRAF inhibitors.

Bilateral areolar leiomyomas in a patient undergoing BRAF inhibition therapy for melanoma.

BRAF inhibition therapy, used to treat melanomas with BRAF mutations, is associated with both neoplastic and non-neoplastic cutaneous side effects including squamous cell carcinomas, warty dyskeratomas, verrucous keratoses, photosensitivity and widespread eruptions that present histopathologically as acantholytic dyskeratosis. We report a case of a patient undergoing BRAF inhibition therapy for disseminated melanoma with a V600E mutation who developed bilateral areolar leiomyomas, one of which was biopsied and the other of which resolved after discontinuation of vemurafenib therapy. To our knowledge, this is the first reported case of a mesenchymal neoplasm developing in association with BRAF inhibition therapy.

15-hydroxyprostaglandin dehydrogenase in colorectal mucosa as a potential biomarker for predicting colorectal neoplasms.

15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is downregulated during the early stages of colorectal carcinogenesis. The aim of the present study was to investigate the potential role of 15-PGDH in normal-appearing colorectal mucosa as a biomarker for predicting colorectal neoplasms. We obtained paired tumor and normal tissues from the surgical specimens of 32 sporadic colorectal cancer patients. mRNA expression of 15-PGDH was measured using a quantitative real-time PCR assay. We evaluated the association between 15-PGDH mRNA expression in normal-appearing mucosa, the presence of synchronous adenoma, and the cumulative incidence of metachronous adenoma. The relative 15-PGDH expression of normal-appearing mucosa in patients with synchronous adenoma was significantly lower than in patients without synchronous adenoma (0.71 vs 1.00, P = 0.044). The patients in the lowest tertile of 15-PGDH expression in normal-appearing mucosa were most likely to have synchronous adenoma (OR: 10.5, P = 0.024). Patients with low 15-PGDH expression in normal-appearing mucosa also demonstrated more advanced stage colorectal cancer (P = 0.045). However, there was no significant difference in the cumulative incidence of metachronous adenoma according to 15-PGDH mRNA expression in normal-appearing mucosa (P = 0.333). Hence, 15-PGDH in normal-appearing colorectal mucosa can be a useful biomarker of field effect for the prediction of sporadic synchronous neoplasms.

Global histone modification of H3K27 correlates with the outcomes in patients with metachronous liver metastasis of colorectal cancer.

BACKGROUND: We evaluated the methylation patterns of histone H3 lysine 27 (H3K27), H3 lysine 36 (H3K36) and the expression of H3K27 methylase EZH2 in patients with colorectal carcinomas with metachronous liver metastasis to search for biomarkers identifying these patients. METHODS: Double 2-mm core tissue microarrays were made from 54 paraffin-embedded samples of primary colorectal adenocarcinomas and corresponding liver metastases and examined using an immunohistochemical analysis of dimethylation and trimethylation in H3K27, H3K36 and EZH2. Positive tumor cell staining for each histone modification (H-score) was used to classify patients into low- and high-staining groups, which were then examined to identify any correlations between the clinicopathological parameters and the clinical outcomes. RESULTS: The H-scores of H3K27me2 were lower in the liver metastases than in the corresponding primary tumors, while the H-scores of H3K36me2 were higher in the liver metastases than in the corresponding primary tumors (P < 0.001). H3K27me2 in the primary tumors correlated with tumor size (P = 0.016), H3K36me2 in the primary tumors correlated with histological type (P = 0.038), and H3K36me3 in the primary tumors correlated with lymph node metastasis (P = 0.017). In addition, lower levels of H3K27me2 in the primary tumors correlated with poorer survival rates (P = 0.039). The multivariate survival analysis showed that the H3K27me2 status is an independent prognostic factor for colorectal cancer patients (P = 0.047). CONCLUSIONS: Our findings suggest that the methylation level of H3K27me2 detected with immunohistochemistry may be an independent prognostic factor for metachronous liver metastasis of colorectal carcinomas.

Effects of azacitidine on matrix metalloproteinase-9 in acute myeloid leukemia and myelodysplasia.

Matrix metalloprotease-9 (MMP9) plays a critical role in acute myeloid leukemia (AML) by increasing the invasive properties of malignant myeloblasts. The role of this enzyme in high-risk myelodysplastic diseases (MDS) and the effect of azacitidine on its expression in MDS and AML have not been studied in detail. In this work, we have analyzed the effect of different concentrations of azacitidine in two well-established, MDS-derived, acute myeloid leukemic cell lines: MOLM-13 and SKM-1. We have demonstrated that 1 µmol/L azacitidine decreases MMP9 DNA methylation levels and that this is correlated with a significant increase in messenger RNA expression in both cell lines. Surprisingly, changes in protein levels were minor. This paradoxic effect is explained by the drug-dependent induction of apoptosis that reduces the amount of active secreting cells. A balance between induced expression and apoptosis was established at an azacitidine concentration of 0.2 µmol/L in MOLM-13 cells. This dose significantly increased the invasive capacity of viable cells, as measured in the Matrigel assay. To evaluate the clinical relevance of this observation, we have examined the effect of azacitidine on MMP9 expression in bone marrow from five patients with MDS, with the finding that this drug significantly increased MMP9 protein levels in all analyzed patients after six cycles of treatment. Based on these results, we conclude that azacitidine increases MMP9 expression and may enhance invasiveness in vitro. Because all five patients relapsed, these findings might explain, at least partially, the clinical failure of the drug and the progression to a more aggressive disease.

15-Hydroxyprostaglandin Dehydrogenase in Colorectal Mucosa as a Potential Biomarker for Predicting Colorectal Neoplasms

15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is downregulated during the early stages of colorectal carcinogenesis. The aim of the present study was to investigate the potential role of 15-PGDH in normal-appearing colorectal mucosa as a biomarker for predicting colorectal neoplasms. We obtained paired tumor and normal tissues from the surgical specimens of 32 sporadic colorectal cancer patients. mRNA expression of 15-PGDH was measured using a quantitative real-time PCR assay. We evaluated the association between 15-PGDH mRNA expression in normal-appearing mucosa, the presence of synchronous adenoma, and the cumulative incidence of metachronous adenoma. The relative 15-PGDH expression of normal-appearing mucosa in patients with synchronous adenoma was significantly lower than in patients without synchronous adenoma (0.71 vs 1.00, P = 0.044). The patients in the lowest tertile of 15-PGDH expression in normal-appearing mucosa were most likely to have synchronous adenoma (OR: 10.5, P = 0.024). Patients with low 15-PGDH expression in normal-appearing mucosa also demonstrated more advanced stage colorectal cancer (P = 0.045). However, there was no significant difference in the cumulative incidence of metachronous adenoma according to 15-PGDH mRNA expression in normal-appearing mucosa (P = 0.333). Hence, 15-PGDH in normal-appearing colorectal mucosa can be a useful biomarker of field effect for the prediction of sporadic synchronous neoplasms.

CHEK2*1100delC heterozygosity in women with breast cancer associated with early death, breast cancer-specific death, and increased risk of a second breast cancer.

PURPOSE: We tested the hypotheses that CHEK2*1100delC heterozygosity is associated with increased risk of early death, breast cancer-specific death, and risk of a second breast cancer in women with a first breast cancer. PATIENTS AND METHODS: From 22 studies participating in the Breast Cancer Association Consortium, 25,571 white women with invasive breast cancer were genotyped for CHEK2*1100delC and observed for up to 20 years (median, 6.6 years). We examined risk of early death and breast cancer-specific death by estrogen receptor status and risk of a second breast cancer after a first breast cancer in prospective studies. RESULTS: CHEK2*1100delC heterozygosity was found in 459 patients (1.8%). In women with estrogen receptor-positive breast cancer, multifactorially adjusted hazard ratios for heterozygotes versus noncarriers were 1.43 (95% CI, 1.12 to 1.82; log-rank P = .004) for early death and 1.63 (95% CI, 1.24 to 2.15; log-rank P < .001) for breast cancer-specific death. In all women, hazard ratio for a second breast cancer was 2.77 (95% CI, 2.00 to 3.83; log-rank P < .001) increasing to 3.52 (95% CI, 2.35 to 5.27; log-rank P < .001) in women with estrogen receptor-positive first breast cancer only. CONCLUSION: Among women with estrogen receptor-positive breast cancer, CHEK2*1100delC heterozygosity was associated with a 1.4-fold risk of early death, a 1.6-fold risk of breast cancer-specific death, and a 3.5-fold risk of a second breast cancer. This is one of the few examples of a genetic factor that influences long-term prognosis being documented in an extensive series of women with breast cancer.

Secondary osteosarcoma arising after treatment for childhood hematologic malignancies.

Secondary osteosarcoma arising after the treatment of hematologic malignancies other than Hodgkin's lymphoma is rare. We report two cases of secondary osteosarcoma arising after treatment for childhood hematologic malignancies (non-Hodgkin's lymphoma and lymphoblastic leukemia). A 10-year-old boy, at the age of 3, was diagnosed with non-Hodgkin's lymphoma. He received chemotherapy, radiation, and bone-marrow transplantation and then was in complete remission. At 6 years, he complained of increasing pain of the right thigh and was diagnosed with osteoblastic osteosarcoma. A 26-year-old man, at the age of 6, was diagnosed as having acute lymphoblastic leukemia (ALL). He received chemotherapy, radiation, and peripheral blood stem cell transplantation (PBSCT). At 11 years after PBSCT, he visited with the complaint of left lumbar swelling. He was diagnosed with chondroblastic osteosarcoma. In both cases alkaline phosphatase (ALP) had already increased prior to the onset of the symptom. We should rule out secondary osteosarcoma at the abnormal elevation of ALP during clinical follow-up of patients after treatment of childhood hematologic malignancies.

Thiopurine methyltransferase genetics is not a major risk factor for secondary malignant neoplasms after treatment of childhood acute lymphoblastic leukemia on Berlin-Frankfurt-Münster protocols.

Thiopurine methyltransferase (TPMT)is involved in the metabolism of thiopurines such as 6-mercaptopurine and 6-thioguanine. TPMT activity is significantly altered by genetics, and heterozygous and even more homozygous variant people reveal substiantially decreased TPMT activity. Treatment for childhood acute lymphoblastic leukemia (ALL) regularly includes the use of thiopurine drugs. Importantly, childhood ALL patients with low TPMT activity have been considered to be at increased risk of developing therapy-associated acute myeloid leukemia and brain tumors. In the present study, we genotyped 105 of 129 patients who developed a secondary malignant neoplasm after ALL treatment on 7 consecutive German Berlin-Frankfurt-Münster trials for all functionally relevant TPMT variants. Frequencies of TPMT variants were similarly distributed in secondary malignant neoplasm patients and the overall ALL patient population of 814 patients. Thus, TPMT does not play a major role in the etiology of secondary malignant neoplasm after treatment for childhood ALL, according to Berlin-Frankfurt-Münster strategies.

Opposite expression pattern of Src kinase Lyn in acute and chronic haematological malignancies.

Lck/yes-related novel (Lyn) tyrosine kinase overexpression has been suggested to be important for leukaemic cell growth making it an attractive target for therapy. By contrast, Lyn deficiency was shown to be responsible for a phenotype resembling myeloproliferative neoplasm (MPN) in mice. We aimed to shed more light on Lyn's role in haematological neoplasm and systematically investigated Lyn expression in MPN, acute and chronic leukaemia subtypes (n = 236). On top, B-cell chronic lymphocytic leukaemia (B-CLL) and chronic myeloid leukaemia significantly overexpressed Lyn when compared to de novo acute lymphoblastic leukaemia, de novo acute myeloid leukaemia (AML) and Philadelphia-chromosome-negative myeloproliferative neoplasms (p < 0.001). Most of acute leukaemia subtypes showed a notable down-regulation of Lyn mRNA but anyhow individual cases were labelled for the active form of Lyn protein. Intriguingly, secondary AML evolved in myelodysplastic syndromes revealed almost undetectable Lyn. Overexpression of Lyn in B-CLL was associated with a significant down-regulation of microRNA-337-5p suggesting that aberrant expression of this particular microRNA could be involved in post-transcriptional control of Lyn mRNA fate. We conclude that tyrosine kinase Lyn contributes to the malignant phenotype in certain leukaemia subtypes and therefore attracts targeted therapy.

Family history, genetic testing, and clinical risk prediction: pooled analysis of CHEK2 1100delC in 1,828 bilateral breast cancers and 7,030 controls.

If breast cancers arise independently in each breast the odds ratio (OR) for bilateral breast cancer for carriers of CHEK2 1100delC should be approximately 5.5, the square of the reported OR for a first primary (OR, 2.34). In the subset of bilateral cases with one or more affected relatives, the predicted carrier OR should be approximately 9. We have tested these predictions in a pooled set of 1,828 cases with 2 primaries and 7,030 controls from 8 studies. The second primary OR for CHEK2 1100delC carriers was 6.43 (95% confidence interval, 4.33-9.56; P < 0.0001), significantly greater than the published estimate for a first primary (P < 0.001) but consistent with its square. The predicted increase in carrier OR with increasing numbers of affected relatives was seen using bilateral cases from the UK (P(trend) = 0.0003) and Finland (P(trend) = 0.37), although not using those from the Netherlands and Russia (P = 0.001 for heterogeneity between countries). Based on a standard genetic model, we predict lifetime risks for CHEK2 1100delC carrier and noncarrier daughters of bilateral breast cancer cases of 37% and 18%, respectively. Our results imply that clinical management of the daughter of a woman with bilateral breast cancer should depend on her CHEK2 1100delC carrier status. This and other moderate penetrance breast cancer susceptibility alleles, together with family history data, will thus identify increasing numbers of women at potentially very high risk. Before such predictions are accepted by clinical geneticists, however, further population-based evidence is needed on the effect of CHEK2 1100delC and other moderate penetrance alleles in women with a family history of breast cancer.

Thiopurine methyltransferase activity is related to the risk of relapse of childhood acute lymphoblastic leukemia: results from the NOPHO ALL-92 study.

Myelotoxicity during thiopurine therapy is enhanced in patients, who because of single nucleotide polymorphisms have decreased activity of the enzyme thiopurine methyltransferase (TPMT) and thus more thiopurine converted into 6-thioguanine nucleotides. Of 601 children with acute lymphoblastic leukemia (ALL) who were treated by the NOPHO ALL-92 protocol, 117 had TPMT genotype determined, whereas for 484 patients only erythrocyte TPMT activity was available. The latter were classified as heterozygous, if TPMT activity was <14 IU/ml, or deficient (<1.0 IU/ml). 526 patients had TPMT wild type, 73 were presumed heterozygous, and two were TPMT deficient. Risk of relapse was higher for the 526 TPMT wild type patients than for the remaining 75 patients (18 vs 7%, P=0.03). In Cox multivariate regression analysis, sex (male worse; P=0.06), age (higher age worse, P=0.02), and TPMT activity (wild type worse; P=0.02) were related to risk of relapse. Despite a lower probability of relapse, patients in the low TPMT activity group did not have superior survival (P=0.82), possibly because of an excess of secondary cancers among these 75 patients (P=0.07). These data suggest that children with ALL and TPMT wild type might have their cure rate improved, if the pharmacokinetics/-dynamics of TPMT low-activity patients could be mimicked without a concurrent excessive risk of second cancers.