HER2 Support Group Forums - Lani/or/Becky.../or anyone else who has

I believe that studies are showing that it simply ISN'T true that glutamine potentially could promote tumor growth...

Here's what I found: (from March 2007)

http://theoncologist.alphamedpress.o.../full/12/3/312

Excerpts:

"...Glutamine is a gluconeogenic nonessential amino acid that is stored primarily in skeletal muscle and liver [14], and is often depleted in stress states, such as malignancy [16]. It serves as the primary carrier of nitrogen and is the main energy source for rapidly proliferating cells. Rapid proliferation of a tumor may deplete glutamine stores and subsequently lead to cancer-related cachexia [17]. Studies have indicated that glutamine supplementation is well tolerated and potentially effective in preventing side effects for patients receiving high-dose chemotherapy and bone marrow transplantation [25]. Supplementation with glutamine can also protect against doxorubicin-induced cardiac toxicity [26] and prevents atrophy of the intestinal mucosa in patients receiving total parenteral nutrition [27]. Preliminary animal studies suggest that glutamine may prevent neurotoxicity caused by vincristine, cisplatin, as well as paclitaxel [28, 29]. Clinically, paclitaxel-induced myalgias and arthralgias have been successfully reduced by glutamine in breast cancer patients [30]. Glutamine supplements may also reduce the severity of peripheral neuropathy in metastatic breast cancer patients receiving high-dose paclitaxel and hematopoietic stem cell transplantation [18]. Interestingly, a byproduct of glutamine metabolism has been identified that protects advanced CRC patients from oxaliplatin-induced neuropathy [13]. 

In the current study, supplementation with glutamine significantly reduced the incidence and severity of peripheral neuropathy as well as the need for dose reduction of oxaliplatin in these patients (Tables 1 and 3). These properties may increase the therapeutic index of oxaliplatin. The potential role of glutamine as a neuroprotectant may be better understood in the context of the current hypothesis explaining chemotherapy-induced neuropathy. A study of circulating nerve growth factor (NGF) levels in cancer patients treated with neurotoxic chemotherapeutic agents found that peripheral neuropathy worsened as serum levels of NGF declined [31]. Moreover, the administration of NGF prevents paclitaxel-induced neuropathy in mice [32]. Because glutamine is known to upregulate NGF mRNA in an animal model [33], glutamine supplements may prevent chemotherapy-induced neuropathy via upregulating the NGF level. On the other hand, it has also been hypothesized that high systemic levels of glutamine may downregulate the conversion of glutamine to an excitatory neuropeptide, glutamate, which may also account for the reduced symptoms observed in patients receiving glutamine [34]...." 


"...A major concern is that glutamine supplements might protect tumor cells from the cytotoxic effects of chemotherapy. However, in the current study, no between-group difference was found in the response to chemotherapy (52.4% versus 47.8%; p = .90) or survival (p = .79; log-rank test). Although in vitro evidence of the dependence of tumor growth on glutamine has deterred its application in cancer patients [36], several studies have failed to show that supplemental glutamine stimulates tumor growth [37, 38]. In fact, accumulating in vivo evidence suggests that glutamine may actually decrease tumor growth, possibly by upregulating the immune system [37, 39]. The net outcome may improve the therapeutic index of oxaliplatin. The overall lymphocyte response (i.e., entry into the cell cycle and proliferation) has been directly correlated with glutamine concentration of the culture medium [40]. In a breast cancer xenograft model, the supplemental glutamine group had higher natural killer cell activity and nearly one half the tumor volume, compared with the placebo group [41]..."