Mammary epithelial cells constitutively expressing Id-1 protein are unable to differentiate, acquire the ability to proliferate, and invade the extracellular matrix. In addition, Id-1 is aberrantly over-expressed in aggressive and metastatic breast cancer cells, as well as in human breast tumor biopsies from infiltrating carcinomas, suggesting Id-1 might be an important regulator of breast cancer progression. We show that human metastatic breast cancer cells become significantly less invasive in vitro and less metastatic in vivo when Id-1 is downregulated by stable transduction with antisense Id-1. Expression of the matrix metalloproteinase MT1-MMP is decreased in proportion to the decrease in Id-1 protein levels, representing a potential mechanism for the reduction of invasiveness. Further, to more accurately recapitulate the biology of and potential therapeutic approaches to tumor metastasis, we targeted Id-1 expression systemically in tumorbearing mice by using a nonviral approach. We demonstrate significant reduction of both Id-1 and MT1-MMP expressions as well as the metastatic spread of 4T1 breast cancer cells in syngeneic BALB͞c mice. In conclusion, our studies have identified Id-1 as a critical regulator of breast cancer progression and suggest the feasibility of developing novel therapeutic approaches to target Id-1 expression to reduce breast cancer metastasis in humans.T he Id (inhibitor of DNA binding) genes were originally identified in murine myoblasts, where they prevented myogenic basic helix-loop-helix (bHLH) transcription factors from binding muscle-specific regulatory elements (1). These transcription factors are key regulators of tissue-specific gene expression in a number of mammalian and nonmammalian organisms, and constitutive expression of Id proteins has been shown to inhibit the differentiation of various tissues (2). bHLH proteins act as obligate dimers, dimerizing through HLH domains, and bind to DNA through the composite basic domains to activate the transcription of target genes containing E-boxes (CANNTG) in their promoters. Id proteins dimerize with bHLH proteins, but the Id-bHLH heterodimers fail to bind to DNA because Id proteins lack the basic domains necessary for DNA interaction.Four members of the Id gene family have been described to date: Id-1, . The different family members localize to different chromosomes and show marked differences in their pattern of expression and function (3, 4). Although the family members are similar in the HLH sequence, the regions outside the HLH domain are distinct for each member and may determine the tissue specificity of Id function, as well as the binding specificity for particular bHLH proteins.We previously developed a line of murine mammary epithelial cells (MEC), SCp2 cells, which originated from a midpregnant mouse mammary gland (5, 6). A role for HLH Id proteins in the differentiation of SCp2 cells was suggested by our finding that Id-1 expression declined to undetectable levels when the cells were induced to differentiate in culture ...
An analysis of failure to control locally recurrent or metastatic melanoma was used to substantiate the value of thickness as a guide to surgical management. There were no local recurrences in patients with melanomas less than 0.76 mm in thickness, regardless of the skin margins excised. The three year actuarial incidence of subsequent regional metastases in patients initially treated by wide local excision (WLE) of their melanoma was directly correlated with tumor thickness (p = <0.001); it was 0% for lesions <0.76 mm, 25% for 0.76 to 1.50 mm lesions, 51% for 1.50 to 3.99 mm lesions and 62% for lesions >4.0 mm in thickness. At five years, patients with melanomas of 1.50 to 3.99 mm thickness who had WLE plus elective regional node dissection (RND) had a calculated 15% incidence of distant metastases and an actuarial survival rate of 83%, while patients with melanomas of the same thickness who had WLE alone as their initial surgical treatment had a 78% incidence of distant metastases and a 37% survival rate (p = 0.001 and 0.01, respectively). In patients with melanomas exceeding 4.0 mm in thickness, the potential benefits of RND were less apparent because of a high risk (>70%) of distant metastases at the time of initial diagnosis. Based upon this analysis, our initial surgical management of melanomas <0.76 is a WLE using a 2.0 cm margin of skin, while thicker lesions are excised using a 3 to 5 cm skin margin. Elective RND is not indicated for lesion C0.76 mm in thickness, but it is considered for 0.76 to 1.50 mm lesions in selected patients and is employed for virtually all patients with lesions exceeding 1.5 mm in thickness. The rationale of elective RND is improved survival in patients with intermediate thickness lesions (0.76 to 3.99 mm) while it is justifiable as a staging procedure for lesions exceeding 4.0 mm thickness.
A randomized, prospective study was designed to compare a continuous with an interrupted technique for closing an abdominal incision. Five hundred seventy-one patients were randomized between the closure methods and stratified as to type of wound: clean, clean-contaminated, or contaminated. In mid-line incisions, the dehiscence rate was 2.0% (5/244) for the continuous group versus 0.9% (2/229) for the interrupted group. The difference was not statistically significant. Ventral hernias formed in 2.0% (4/201) of the continuous group vs. 0.5% (1/184) of the interrupted group. The type of wound had no influence on the results. In oblique incisions, 0% (0/39) of wounds closed continuously dehised while 2% (1/50) of incisions closed interruptedly dehised. No ventral hernias formed. Further analysis of the data indicated that dehiscence was more likely related to improper surgical technique than to the method of closure. An abdominal incision could be closed with a continuous suture in approximately half the time required for placing interrupted sutures (20 vs. 40 minutes). A continuous closure is preferred because it is more expedient and because it has the same incidence of wound disruption compared with an interrupted closure.
The optimal treatment for squamous and cloacogenic tumors of the anorectum is controversial. Radical surgery, limited surgery, and radiotherapy (XRT) are all potentially curative. This study was undertaken to determine which patients are candidates for each type of treatment and which would benefit from combined treatment. The records of 192 patients treated at this institution between 1954 and 1979 with the diagnosis of squamous or cloacogenic carcinoma of the anorectum were retrospectively reviewed. A subgroup of 132 patients undergoing abdominal perineal resection (APR) was analyzed to determine prognostic factors for these tumors. No survival difference was observed between the two histologic types (P = 0.51). Prognostic variables significant at P = 0.05 or better were sex, size, nodal status, and level of invasion. A new staging system is proposed that utilizes tumor size, invasion, grade, and nodal status. Actuarial 10‐year survival was 100%, 76%, 29%, and 0% for Stages A, B, C and D, respectively (P values 0.22, 0.0007, and 0.01, respectively). Twelve patients undergoing APR received postoperative XRT; when compared by stage with APR alone no survival difference can be shown, although there is a trend towards fewer local recurrences. Of 26 patients (14 Stage B, 12 Stage C) receiving preoperative XRT (average 4000 R) before APR, 10 had inoperable tumors prior to XRT. All became operable. Eight patients had negative surgical margins and survival was equivalent stage for stage to the operable group (Stage B 78%, 5‐year survival; Stage C 43%, 5‐year survival). Eleven patients had no demonstrable primary tumor after XRT, although three had nodal metastasis. Five‐year survival was 83% for this group. Thirty‐one local recurrences were retreated for cure by surgery, XRT, or combination. Actuarial 5‐year survival after retreatment was 38%. Thirty metachronous inguinal metastases were seen, 20 were retreated for cure, 18 by inguinal lymphadenectomy. Actuarial 5‐year survival was 42%. Using a new staging system based on analysis of prognostic parameters for this disease, the outcome of combined surgery and XRT is compared. The efficacy of preoperative XRT for inoperable tumors is demonstrated. An appreciable salvage rate for local or inguinal recurrence was observed. Cancer 53:1285‐1293, 1984.
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