Frederic J. Kaye

A Randomized Trial Comparing Combination Electron-Beam Radiation and Chemotherapy with Topical Therapy in the Initial Treatment of Mycosis Fungoides

Mycosis fungoides is a T-cell lymphoma that arises in the skin and progresses at highly variable rates. Nonradomized studies have suggested that early aggressive therapy may improve the prognosis in this usually fatal disease. We studied 103 patients with mycosis fungoides, who, after complete staging, were randomly assigned to receive either combination therapy, consisting of 3000 cGy of electron-beam radiation to the skin combined with parenteral chemotherapy with cyclophosphamide, doxorubicin, etoposide, and vincristine (n = 52) or sequential topical treatment (n = 51). The prognostic factors were well balanced in the two groups. Combined therapy produced considerable toxicity: 12 patients required hospitalization for fever and transient neutropenia, 5 had congestive heart failure, and 2 were later found to have acute nonlymphocytic leukemia. Patients receiving combined therapy had a significantly higher rate of complete response, documented by biopsy, than patients receiving conservative therapy (38 percent vs. 18 percent; P = 0.032). After a median follow-up of 75 months, however, there was no significant difference between the treatment groups in disease-free or overall survival. We conclude that early aggressive therapy with radiation and chemotherapy does not improve the prognosis for patients with mycosis fungoides as compared with conservative treatment beginning with sequential topical therapies.

Histopathologic staging at initial diagnosis of mycosis fungoides and the Sézary syndrome. Definition of three distinctive prognostic groups.

STUDY OBJECTIVE To determine the optimal staging evaluation at the time of initial diagnosis of mycosis fungoides or the Sézary syndrome. DESIGN Retrospective review of a uniformly staged inception cohort. SETTING Single-institution tertiary care center. PATIENTS 152 consecutive patients who had mycosis fungoides with or without the Sézary syndrome within 6 months of the initial definitive diagnosis. INTERVENTION A detailed staging evaluation including physical examination, routine laboratory studies, chest roentgenogram, lymphangiogram, peripheral blood smear, lymph node biopsy, bone marrow aspirate or biopsy, and liver biopsy in selected patients. MEASUREMENTS AND MAIN RESULTS Univariate adverse prognostic features at initial diagnosis in patients with mycosis fungoides included (P less than 0.01) one or more cutaneous tumors or generalized erythroderma, adenopathy, blood smear involvement with Sézary cells, lymph node effacement, eosinophilia, and visceral involvement. Important, independent prognostic factors in a multivariate analysis are the presence of visceral disease and type of skin involvement. CONCLUSIONS A staging system based on histopathologic evaluation of skin, lymph nodes, blood, and visceral sites provides more comprehensive prognostic information than clinical evaluation of skin disease and adenopathy. Patients may be divided at initial presentation into three prognostic groups: good-risk patients, who have plaque-only skin disease without lymph node, blood, or visceral involvement (median survival, greater than 12 years); intermediate-risk patients, who have cutaneous tumors, erythroderma, or plaque disease with node or blood involvement but no visceral disease or node effacement (median survival, 5 years); and poor-risk patients, who have visceral involvement or node effacement (median survival, 2.5 years).

RB and cyclin dependent kinase pathways: defining a distinction between RB and p16 loss in lung cancer.

The genetic components of the RB:CDK:cyclin:p16 tumor suppressor pathway undergo mutational and epigenetic alterations in a wide range of human cancers and serve as critical targets for inactivation by the transforming oncoproteins of several DNA tumor viruses. Lung cancer has been a useful model system for these studies as it was the first tumor to demonstrate an important role for RB in the genesis of a common adult malignancy and was also the first human cancer to demonstrate genetic evidence for a multi-component RB:p16 tumor suppressor pathway. Lung tumorigenesis, however, is a complex disease process that requires longstanding carcinogen exposure in order to acquire somatic alterations at many distinct genetic loci. Understanding the multifunctional properties of RB to regulate cell proliferation, differentiation, and apoptosis and how they relate to the sequential accumulation of other clonal gene defects will be essential in order to understand the specific patterns of gene inactivation observed in different subtypes of lung cancer and to fulfill the promise of ‘molecular target’ therapeutics.

A Study of MECT1-MAML2 in Mucoepidermoid Carcinoma and Warthin's Tumor of Salivary Glands

The t(11;19)(q21;p13) chromosomal translocation has been described in two distinct types of salivary gland neoplasms: mucoepidermoid carcinoma (MEC) and Warthins tumor (WT). Since this translocation has been recently shown to generate a MECT1-MAML2 fusion gene, we evaluated 10 primary MEC and seven primary WT to further define the molecular association of these two entities using cytogenetic, as well as in situ hybridization (ISH) and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses directed against the fusion gene. A karyotype was established in all neoplasms except for two MEC cases. Of the eight karyotyped MECs, five showed the t(11;19)(q21;p13), two had a normal karyotype, and one case presented a -Y and +X. Three of the WT revealed a normal karyotype and four had several abnormalities which did not involve chromosomes 11 and 19. ISH analysis performed in cytogenetic suspension and/or in tumor paraffin sections demonstrated MAML2 rearrangement in 7 of 10 cases of MEC: all five cases with t(11;19), one case with normal karyotype, and one unkaryotyped case. RT-PCR analysis confirmed the expression of the MECT1-MAML2 gene in all MEC cases that were positive by ISH analysis. Neither the t(11;19) nor MECT1-MAML2 was detected in any case of WT, nor in control samples from polymorphous low-grade adenocarcinoma, acinic cell carcinoma, or normal parotid gland tissue. We have demonstrated that ISH and RT-PCR are sensitive methods for detecting MECT1-MAML2 in MEC. In contrast, we did not detect the t(11;19) nor MECT1-MAML2 expression in seven cases of WT.

Altered LKB1/CREB-regulated transcription co-activator (CRTC) signaling axis promotes esophageal cancer cell migration and invasion.

LKB1 is a tumor susceptibility gene for the Peutz–Jeghers cancer syndrome and is a target for mutational inactivation in sporadic human malignancies. LKB1 encodes a serine/threonine kinase that has critical roles in cell growth, polarity and metabolism. A novel and important function of LKB1 is its ability to regulate the phosphorylation of CREB-regulated transcription co-activators (CRTCs) whose aberrant activation is linked with oncogenic activities. However, the roles and mechanisms of LKB1 and CRTC in the pathogenesis of esophageal cancer have not been previously investigated. In this study, we observed altered LKB1–CRTC signaling in a subset of human esophageal cancer cell lines and patient samples. LKB1 negatively regulates esophageal cancer cell migration and invasion in vitro. Mechanistically, we determined that CRTC signaling becomes activated because of LKB1 loss, which results in the transcriptional activation of specific downstream targets including LYPD3, a critical mediator for LKB1 loss-of-function. Our data indicate that de-regulated LKB1–CRTC signaling might represent a crucial mechanism for esophageal cancer progression.

CRTC1/MAML2 fusion transcript in Warthin's tumor and mucoepidermoid carcinoma: Evidence for a common genetic association

Translocations and gene fusions have an important early role in tumorigenesis. The t(11;19) translocation and its CRTC1/MAML2 fusion transcript have been identified in several examples of both Warthins tumor and mucoepidermoid carcinoma and are believed to be associated with the development of a subset of these tumors. To determine whether Warthins tumor and mucoepidermoid carcinoma are genetically related, we used reverse transcriptase‐polymerase chain reaction and DNA sequencing to analyze microdissected components of three tumors consisting of Warthins tumor and mucoepidermoid carcinoma. We also investigated a metastatic melanoma to Warthins tumor and a Warthins carcinoma of the parotid gland for comparison. The fusion transcript was identified in both Warthins tumor and matching mucoepidermoid carcinoma components of all three tumors, in the Warthins carcinoma, and in the Warthins tumor component but not in the metastatic melanoma. The results provide evidence for a link between the t(11;19) fusion gene and the development of a subset of Warthins tumors with concurrent mucoepidermoid carcinoma and possible malignant transformation to Warthins carcinoma. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat.

Disruption of Myc-Tubulin Interaction by Hyperphosphorylation of c-Myc during Mitosis or by Constitutive Hyperphosphorylation of Mutant c-Myc in Burkitt's Lymphoma

ABSTRACT Somatic mutations at Thr-58 of c-Myc have been detected in Burkitts lymphoma (BL) tumors and have been shown to affect the transforming potential of the Myc oncoprotein. In addition, the N-terminal domain of c-Myc has been shown to interact with microtubules in vivo, and the binding of c-Myc to α-tubulin was localized to amino acids 48 to 135 within the c-Myc protein. We demonstrate that c-Myc proteins harboring a naturally occurring mutation at Thr-58 from BL cell lines have increased stability and are constitutively hyperphosphorylated, which disrupts the in vivo interaction of c-Myc with α-tubulin. In addition, we show that wild-type c-Myc–α-tubulin interactions are also disrupted during a transient mitosis-specific hyperphosphorylation of c-Myc, which resembles the constitutive hyperphosphorylation pattern of Thr-58 in BL cells.

Differential specificity for binding of retinoblastoma binding protein 2 to RB, p107, and TATA-binding protein.

The growth suppressor activities of the RB and p107 products are believed to be mediated by the reversible binding of a heterogeneous family of cellular proteins to a conserved T/E1A pocket domain that is present within both proteins. To study the functional role of these interactions, we examined the properties of cellular retinoblastoma binding protein 2 (RBP2) binding to RB, p107, and the related TATA-binding protein (TBP) product. We observed that although RBP2 bound exclusively to the T/E1A pocket of p107, it could interact with RB through independent T/E1A and non-T/E1A domains and with TBP only through the non-T/E1A domain. Consistent with this observation, we found that a mutation within the Leu-X-Cys-X-Glu motif of RBP2 resulted in loss of ability to precipitate p107, while RB- and TBP-binding activities were retained. We located the non-T/E1A binding site of RBP2 on a 15-kDa fragment that is independent from the Leu-X-Cys-X-Glu motif and encodes binding activity for RB and TBP but does not interact with p107. Despite the presence of a non-T/E1A binding site, however, recombinant RBP2 retained the ability to preferentially precipitate active hypophosphorylated RB from whole-cell lysates. In addition, we found that cotransfection of RBP2 can reverse in vivo RB-mediated suppression of E2F activity. These findings confirm the differential binding specificities of the related RB, p107, and TBP proteins and support the presence of multifunctional domains on the nuclear RBP2 product which may allow complex interactions with the cellular transcription machinery.

Mutation-associated fusion cancer genes in solid tumors

Chromosomal translocations and fusion oncogenes serve as the ultimate biomarker for clinicians as they show specificity for distinct histopathologic malignancies while simultaneously encoding an etiologic mutation and a therapeutic target. Previously considered a minor mutational event in epithelial solid tumors, new methodologies that do not rely on the detection of macroscopic cytogenetic alterations, as well as access to large series of annotated clinical material, are expanding the inventory of recurrent fusion oncogenes in both common and rare solid epithelial tumors. Unexpectedly, related assays are also revealing a high number of tandem or chimeric transcripts in normal tissues including, in one provocative case, a template for a known fusion oncogene. These observations may force us to reassess long-held views on the definition of a gene. They also raise the possibility that some rearrangements might represent constitutive forms of a physiological chimeric transcript. Defining the chimeric transcriptome in both health (transcription-induced chimerism and intergenic splicing) and disease (mutation-associated fusion oncogenes) will play an increasingly important role in the diagnosis, prognosis, and therapy of patients with cancer. [Mol Cancer Ther 2009;8(6):1399–408]

Protein expression of the RB-related gene family and SV40 large T antigen in mesothelioma and lung cancer.

Mutational inactivation of the RB-related gene RBL2/p130 has been reported as a common and important prognostic factor in human lung cancer. To examine the role of the RB-related gene family in lung cancer we analysed the protein expression of the RB gene in cell lines obtained from 83 patients with small cell lung cancer (SCLC) and 114 patients with non-SCLC that included 21 novel lung tumor samples. While we detected five new SCLC with mutant RB expression (RB inactivation in 75/83; 90.4%), we did not detect any RB mutations in the new non-SCLC cell lines (RB inactivation in 13/114 non-SCLC and mesothelioma; 11.4%). In addition, we detected expression of a full-length RBL1/p107 and RBL2/p130 species in every sample tested (RBL1 or RBL2 inactivation in 0/69) and confirmed that both RB-related gene products retain functional binding activity to the E1A viral oncoprotein. Since expression of SV40 Large T antigen (Tag) has been reported in a subset of human lung tumors where it may inactivate RBL1 and RBL2, we also examined mesothelioma and non-mesothelioma lung tumors for Tag expression. Although we detected a faint 85 kDa protein species using specific anti-Tag antibodies, this signal migrated slightly faster than Tag extracted from Cos7 cells and did not exhibit binding activity to the RB or RBL1 proteins. Finally, we subjected 11 lung cancer cell lines to nucleotide sequencing and did not detect mutations within the C-terminal RBL2 exons 19–22 as recently reported. While the RB/p16 tumor suppressor pathway is targeted for mutations in 100% of lung cancers, mutational inactivation of the related RBL1 and RBL2 genes is a rare event.