A prominent feature of most if not all cancers is a striking genetic instability, leading to ongoing accrual of mutational changes, some of which underlie tumor progression, including acquisition of invasiveness, drug resistance, and metastasis. Thus, the molecular basis for the generation of this genetic diversity in cancer cells has important implications in understanding cancer progression. Here we report that homologous recombination (HR) activity is elevated in multiple myeloma (MM) cells and leads to an increased rate of mutation and progressive accumulation of genetic variation over time. We demonstrate that the inhibition of HR activity in MM cells by small inhibitory RNA (siRNAs) targeting recombinase leads to significant reduction in the acquisition of new genetic changes in the ge- IntroductionGenetic changes observed at the chromosomal level or at the nucleotide sequence level are associated with the development and progression of malignant phenotypes. Although some specific cancers are associated with and attributed to specific cytogenetic and molecular aberrations, for example, chronic myelogenous leukemia or acute promyelocytic leukemia, the majority of cancers display a complex spectra of diverse genetic alterations apparent at diagnosis and acquire additional changes with progression of the disease. 1 Because the large-scale chromosomal alterations that arise frequently in cancer cells occur infrequently in normal cells, [2][3][4] it implies that the control mechanisms that maintain the integrity of chromosomes in normal cells are disrupted in cancer cells.A variety of intrinsic or extrinsic chemical as well as physical factors damage DNA in living organisms which, if not repaired, can lead to mutations and cellular transformation. The best known machinery involved in repairing potentially lethal DNA damage, especially double-strand breaks, is genetic recombination. 5 In fact the repair of DNA lesions may account for majority of the recombination occurring in mitosis. 6 Recombination plays an important role in maintaining the genetic integrity of a cell, including DNA repair 7 and proper segregation of chromosomes in meiosis. 8 In the normal cellular environment, recombination-associated proteins are highly regulated, precise, and exhibit considerable specificity for DNA sequences, which have either an extensive homology or a characteristic signal sequence. However, with its significant ability to modify DNA, if dysregulated, it can lead to genomic instability. Recombination can be induced by several chemicals, radiation, and oncogenic viruses. [9][10][11][12][13][14] The induction or overexpression of a recombination pathway may result in DNA rearrangements, leading to oncogene activation 15 and/or the loss of hemizygous functional alleles of tumor suppressor genes.Aberrant or dysregulated recombination has been implicated in chromosome translocation, 9,16,17 gene amplification, 18 and telomere maintenance 19 and may therefore underlie the chromosomal aberrations observed with high frequency i...

The presence of a metaphase cytogenetic abnormality (CA) is the key negative predictor of outcome in patients with multiple myeloma (MM). Gene expression profiling (GEP) of such patients showed increased expression of NY-ESO-1 compared to patients with normal cytogenetics (60% versus 31%; P ‫؍‬ .004). NY-ESO-1 was also highly expressed in relapsing MM especially patients with CA (100% versus 60.7%; P < .001). GEP findings were confirmed at the protein level by immunostaining of marrow biopsies for NY-ESO-1. We detected spontaneous NY-ESO-1-specific antibodies by enzymelinked immunosorbent assay in 33% of patients with NY-ESO-1 ؉ MM, especially in CA patients (9 of 13; 70%), but in none of the NY-ESO-1 ؊ patients with MM (n ‫؍‬ 27) or healthy donors (n ‫؍‬ 21 IntroductionDuring the past 10 years, numerous human tumor-associated antigens (Ags) have been identified, either by screening cDNA libraries with sera derived from cancer patients containing an antibody (Ab) to a tumor-associated Ag (SEREX) or by using T lymphocytes specific for tumor peptides presented in the context of specific HLA alleles. [1][2][3][4][5][6][7][8][9][10][11] The most rapidly expanding group of tumor Ags are the cancer/testis (C/T) Ags, which are either not expressed or are present at very low levels in normal tissues except the testes and perhaps the placenta. 12,13 Because the testes are not patrolled by the immune system, expression of C/T Ags in this environment is not harmful.Of the C/T Ags described thus far, NY-ESO-1 is among the most immunogenic with not only well-documented spontaneous [14][15][16][17][18][19][20] and vaccine-induced immunity, but also clinical responses in a substantial percentage of chemorefractory cancers. 19,21 NY-ESO-1 mRNA is found in approximately 20% to 40% of tumors including melanoma, prostate, transitional cell bladder, breast, lung, medullary thyroid, squamous head and neck, and cervical carcinoma. 12,14,[22][23][24][25][26][27] Because it is expressed in such a wide variety of tumors, NY-ESO-1 offers a unique opportunity to develop a broad-spectrum tumor-specific cancer vaccine.High-dose chemotherapy with autologous peripheral blood stem cell transplantation (auto-PBSCT) has significantly improved the outcome of patients with multiple myeloma (MM). [28][29][30][31][32][33][34][35][36][37] We and others have shown that the presence of cytogenetic abnormalities (CAs) is the most powerful prognosticator for poor outcome. [38][39][40][41][42][43][44][45] Intensification of treatment in our Total Therapy II (TTII) protocol has resulted in additional improvement in event-free (EFS) and overall survival (OS) of patients without CAs (67% of patients). However, no such improvement has yet been observed for patients with CAs (33% of patients). 41,43,46 Fewer than 10% of patients treated with tandem auto-PBSCT protocols remain in long-term remission and are considered "operationally cured." 40 These data highlight the urgent need for new approaches to improve diseasefree survival in such patients.We analyzed ou...

Epigallocatechin-3-gallate (EGCG), a polyphenol extracted from green tea, is an antioxidant with chemopreventive and chemotherapeutic actions. Based on its ability to modulate growth factor-mediated cell proliferation, we evaluated its efficacy in multiple myeloma (MM).