Molecular mechanisms of castration-resistant prostate cancer progression.

Hormone-refractory prostate cancer is the result of regrowth of prostate cancer cells that have adapted to the hormone-deprived environment of the prostate. The process by which castration-resistant prostate cancer (CRPC) cells are generated appears to be varied. The complex mechanism of hormone resistance has been the topic of research in most laboratories that have analyzed the process from different angles.

Uniparentalism in sporadic colorectal cancer is independent of imprint status, and coordinate for chromosomes 14 and 18.

Our previous allelotyping studies of 59 sporadic colorectal cancers revealed that loss of heterozygosity is most frequent for regions of chromosomes 14 and 18. Yet subsequent BAC microarray comparative genomic hybridization studies of the same tumor DNAs showed no corresponding pattern of copy number alteration for chromosome 14. To clarify this apparent discrepancy, we utilized hybridization to SNP microarrays; this revealed frequent uniparentalism for chromosome 14 and for chromosome 18.

Colorectal cancers in patients with the (9A/6A) polymorphism of TGFBR1 exhibit lesser inter-(simple sequence repeat) PCR genomic instability and present clinically at greater age.

TGFbeta is involved in the response to DNA damage and signaling the cell cycle checkpoint response, in large part achieved by modulating the activity of the ATM kinase. We have investigated if the presence of a common polymorphism in the TGFbeta receptor TGFBR1 might impact genomic instability in human colorectal cancer. In order to obtain statistically significant numbers of patients with the lesser polymorphism, 177 colorectal cancer patients were genotyped for either the major form of the TGFBR1 receptor gene, homozygous for an internal segment of 9 alanines (9A/9A), or the lesser form, heterozygous for the polymorphism containing 6 alanines (9A/6A).

Analysis of inter-(simple sequence repeat) PCR products from human colorectal cancers.

Genomic instability is a fundamental characteristic of solid tumors, and understanding genomic instability should significantly clarify the process of tumorigenesis. We adapted the sampling technique of inter-(simple sequence repeat) PCR [inter-(SSR) PCR] to measure genetic alterations between simple sequence repeats in colorectal tumors. It becomes important to precisely define both normal and altered inter-(SSR) PCR products.

Development of an androgen-deprivation induced and androgen suppressed human prostate cancer cell line.

Background: Emergence of recurrent cells during androgen-deprivation therapy and intermittent androgen suppression therapy suggest that a subset of prostate cancer cells survive and proliferate in the androgen deprivation condition. Some of the recurrent cells that emerge during the androgen-deprivation therapy and intermittent androgen suppression therapy could be suppressed by replacement of androgen. In an attempt to recapitulate the clinical phenomenon, we developed an androgen-deprivation induced and androgen suppressed human prostate cancer cell line.

Comparative genomic instabilities of thyroid and colon cancers.

Objectives: To assess the forms and extent of genomic instability in thyroid cancers and colorectal neoplasms and to determine if such measurements could explain the generally excellent prognosis of thyroid malignant neoplasms compared with colon carcinoma.

Design: Tumor genome analyses. Genomic instability was measured by the following 4 methods, listed in ascending order based on the size of events detected: inter-simple sequence repeat polymerase chain reaction (ISSR-PCR), fractional allelic loss (FAL) analysis, array-based comparative genomic hybridization (aCGH), and spectral karyotyping (SKY).

Genomic profiles of colorectal cancers differ based on patient smoking status.

Human sporadic colorectal cancer is the result of a lengthy somatic evolutionary process facilitated by various forms of genomic instability. Such instability arises endogenously from mutations in genes whose role is to preserve genomic integrity, and exogenously from environmental agents that generate genomic damage. We have found that cigarette smoking shifts the genomic profiles and genomic instability patterns of colorectal carcinomas.