SNPはがん食欲不振と関連なし

がん患者の食欲不振に遺伝的な原因があるかどうかを探索した論文を紹介します。

Tora S. Solheim, et al: Is there a genetic cause of appetite loss?—an explorative study in 1,853 cancer patients. Journal of Cachexia, Sarcopenia and Muscle, doi:10.1007/s13539-012-0064-8

下記HPで全文見ることができます。
http://www.springerlink.com/content/j306428541v1g811/fulltext.pdf

がん患者では食欲不振、体重減少を認めることが多いですが、認めない患者もいます。そこで遺伝的な原因として、93の一塩基多型（SNP、single-nucleotide polymorphisms）が、がん患者の食欲不振と関連しているかを探索的に調べました。

一塩基多型はWikipediaを参照してください。
http://ja.wikipedia.org/wiki/%E4%B8%80%E5%A1%A9%E5%9F%BA%E5%A4%9A%E5%9E%8B

結果ですが、一塩基多型がん患者の食欲不振には統計学的に有意な関連を認めませんでした。この結果で遺伝的な関与がないとは言い切れませんが、単一の一塩基多型が、がん患者の食欲不振に大きな影響を与えていることはなさそうという結論です。

がん患者の食欲不振に、単一要因ではなく多要因で遺伝が関与している可能性はあるかもしれません。薬物療法（EPAや六君子湯など）がどんな患者に効きそうでどんな患者に効かなそうかくらいでも、遺伝研究でわかるようになると臨床的には嬉しいですね。

Abstract
Background Appetite loss has a major impact on cancer patients. It is exceedingly prevalent, is a prognostic indicator and is associated with inferior quality of life. Cachexia is a multi-factorial syndrome defined by a negative protein and energy balance, driven by a variable combination of reduced food intake and abnormal metabolism. Not all cancer patients that experience weight loss have appetite loss, and the pathophysiology between cachexia and appetite loss may thus be different. Knowledge of pathophysiology of appetite loss in cancer patients is still limited. The primary object of this study was to explore the association with 93 predefined candidate single-nucleotide polymorphisms (SNPs) and appetite loss in cancer patients to possibly generate new theories of the pathophysiology of the condition.

Methods A total of 1,853 cancer patients were phenotyped according to appetite loss and then genotyped.

Results After allowing for multiple testing, there was no statistically significant association between any of the SNPs analysed and appetite loss. The ten most significant SNPs in the co-dominant model had observed odds ratios varying from 0.72 to 1.28.

Conclusions This large exploratory study could not find any associations with loss of appetite and 93 SNPs with a potential to be involved in appetite loss in cancer patients. This does not however rule out genes putative role in the development of the symptom, but the observed odds ratios are close to one which makes it unlikely that any of the individual SNPs explored in the present study have great importance.