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Tryptophan degradation in women with breast cancer: a pilot study.

Lyon DE, Walter JM, Starkweather AR, Schubert CM, McCain NL - BMC Res Notes (2011)

Bottom Line: In addition, these biological factors have been associated with the development and severity of neuropsychiatric syndromes, including major depressive disorder.Plasma concentrations of tryptophan, kynurenine, and tyrosine were determined.The kynurenine to tryptophan ratio (KYN/TRP) was used to estimate indoleamine 2,3-dioxygenase activity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Family and Community Health Nursing, Virginia Commonwealth University School of Nursing, 1100 East Leigh Street, Richmond, Virginia, 23298, USA. delyon@vcu.edu.

ABSTRACT

Background: Altered tryptophan metabolism and indoleamine 2,3-dioxygenase activity are linked to cancer development and progression. In addition, these biological factors have been associated with the development and severity of neuropsychiatric syndromes, including major depressive disorder. However, this biological mechanism associated with both poor disease outcomes and adverse neuropsychiatric symptoms has received little attention in women with breast cancer. Therefore, a pilot study was undertaken to compare levels of tryptophan and other proteins involved in tryptophan degradation in women with breast cancer to women without cancer, and secondarily, to examine levels in women with breast caner over the course of chemotherapy.

Findings: Blood samples were collected from women with a recent diagnosis of breast cancer (n = 33) before their first cycle of chemotherapy and after their last cycle of chemotherapy. The comparison group (n = 24) provided a blood sample prior to breast biopsy. Plasma concentrations of tryptophan, kynurenine, and tyrosine were determined. The kynurenine to tryptophan ratio (KYN/TRP) was used to estimate indoleamine 2,3-dioxygenase activity. On average, the women with breast cancer had lower levels of tryptophan, elevated levels of kynurenine and tyrosine and an increased KYN/TRP ratio compared to women without breast cancer. There was a statistically significant difference between the two groups in the KYN/TRP ratio (p = 0.036), which remained elevated in women with breast cancer throughout the treatment trajectory.

Conclusions: The findings of this pilot study suggest that increased tryptophan degradation may occur in women with early-stage breast cancer. Given the multifactorial consequences of increased tryptophan degradation in cancer outcomes and neuropsychiatric symptom manifestation, this biological mechanism deserves broader attention in women with breast cancer.

No MeSH data available.


Related in: MedlinePlus

Change in Biological Factors from Time 1 to Time 2 for Women with Breast Cancer.
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Figure 2: Change in Biological Factors from Time 1 to Time 2 for Women with Breast Cancer.

Mentions: Variabilities in KYN and KYN/TRP ratios were much higher in the women with BCA than in women without BCA (comparison group) and noticeably higher levels of TYR were found for women with BCA (Figure 1). Women with BCA had a significantly higher KYN/TRP ratio (p = 0.036) than the women in the comparison group. There were no statistically significant differences between these women with regard to KYN (p = -0.18), TRP (p = 0.16), or TYR (p = 0.54). Means by measurement time-point for the women with BCA are plotted in Figure 2 and listed in Table 2. Although there were decreases in KYN, TRP, KYN/TRP ratio and increases in TYR in women with BCA from baseline to T2, these changes were not statistically significant.


Tryptophan degradation in women with breast cancer: a pilot study.

Lyon DE, Walter JM, Starkweather AR, Schubert CM, McCain NL - BMC Res Notes (2011)

Change in Biological Factors from Time 1 to Time 2 for Women with Breast Cancer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117722&req=5

Figure 2: Change in Biological Factors from Time 1 to Time 2 for Women with Breast Cancer.
Mentions: Variabilities in KYN and KYN/TRP ratios were much higher in the women with BCA than in women without BCA (comparison group) and noticeably higher levels of TYR were found for women with BCA (Figure 1). Women with BCA had a significantly higher KYN/TRP ratio (p = 0.036) than the women in the comparison group. There were no statistically significant differences between these women with regard to KYN (p = -0.18), TRP (p = 0.16), or TYR (p = 0.54). Means by measurement time-point for the women with BCA are plotted in Figure 2 and listed in Table 2. Although there were decreases in KYN, TRP, KYN/TRP ratio and increases in TYR in women with BCA from baseline to T2, these changes were not statistically significant.

Bottom Line: In addition, these biological factors have been associated with the development and severity of neuropsychiatric syndromes, including major depressive disorder.Plasma concentrations of tryptophan, kynurenine, and tyrosine were determined.The kynurenine to tryptophan ratio (KYN/TRP) was used to estimate indoleamine 2,3-dioxygenase activity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Family and Community Health Nursing, Virginia Commonwealth University School of Nursing, 1100 East Leigh Street, Richmond, Virginia, 23298, USA. delyon@vcu.edu.

ABSTRACT

Background: Altered tryptophan metabolism and indoleamine 2,3-dioxygenase activity are linked to cancer development and progression. In addition, these biological factors have been associated with the development and severity of neuropsychiatric syndromes, including major depressive disorder. However, this biological mechanism associated with both poor disease outcomes and adverse neuropsychiatric symptoms has received little attention in women with breast cancer. Therefore, a pilot study was undertaken to compare levels of tryptophan and other proteins involved in tryptophan degradation in women with breast cancer to women without cancer, and secondarily, to examine levels in women with breast caner over the course of chemotherapy.

Findings: Blood samples were collected from women with a recent diagnosis of breast cancer (n = 33) before their first cycle of chemotherapy and after their last cycle of chemotherapy. The comparison group (n = 24) provided a blood sample prior to breast biopsy. Plasma concentrations of tryptophan, kynurenine, and tyrosine were determined. The kynurenine to tryptophan ratio (KYN/TRP) was used to estimate indoleamine 2,3-dioxygenase activity. On average, the women with breast cancer had lower levels of tryptophan, elevated levels of kynurenine and tyrosine and an increased KYN/TRP ratio compared to women without breast cancer. There was a statistically significant difference between the two groups in the KYN/TRP ratio (p = 0.036), which remained elevated in women with breast cancer throughout the treatment trajectory.

Conclusions: The findings of this pilot study suggest that increased tryptophan degradation may occur in women with early-stage breast cancer. Given the multifactorial consequences of increased tryptophan degradation in cancer outcomes and neuropsychiatric symptom manifestation, this biological mechanism deserves broader attention in women with breast cancer.

No MeSH data available.


Related in: MedlinePlus